The `resolver` argument was only used from external packages which can
be migrated off this utility.

The `checked` argument was only used to allow `spawnHybrid` APIs to run
code without asserts, but we want all test code to run with asserts,
including server side utilities.

The breaking changes were handled in #1125

* Flexible Coverage API

Closes #1141

Bump min SDK in all packages for safety. Restore use of for-loop
elements in a top level variable since they work in this SDK.

Towards #1141

Work around the bug in the SDK by switching back to `..addAll`. After we
publish this version that works we can bump the min SDK.

Prepare to publish.

The field is no longer used by pub and triggers a warning on publish.

- Bump to feature version change in `test`.
- Drop `-dev` from pubspecs.
- Pin to latest `test_core` from `test`.

Remove TODO comments waiting for things that will never change or that
we don't intend to take action on.

- https://github.com/dart-lang/sdk/issues/22977 is closed as not
  planned.
- Dart 2 does not support importing `dart:io` in cross platform code.
- Setting the exit code is not supported on web.
- We plan on keeping `executable.dart` under lib to allow reuse from
  other packages internally.
- We don't plan on trying to support `spawnHybridUri` outside of the
  test runner.
- `executable.main` is now declared to return a `Future`.
- We don't intend to take a dependency on `json_schema`.

Flutter pins package dependencies, including all transitive dependencies.

Because test_api depends on pedantic, Flutter pins that dependency.

However, pedantic is only depended on for the `unawaited` function, which is a one-line piece of code.

This will enable resolution of https://github.com/flutter/flutter/issues/48246 without requiring Flutter to unpin its dependencies, and with a very small overhead on test_api to not re-import pedantic :)  This helps downstream consumers who want to depend on the package for the actual analysis options files.

Also related: https://github.com/dart-lang/pedantic/issues/46

- always_declare_return_types
- annotate_overrides
- await_only_futures
- omit_local_variable_types
- prefer_collection_literals
- prefer_conditional_assignment
- prefer_final_fields
- prefer_for_elements_to_map_fromiterable
- prefer_if_null_operators
- prefer_spread_collections
- unnecessary_this
- use_function_type_syntax_for_parameters

Bump min SDK to 2.3.0 everywhere to allow using spreads in collection
literals.

Skip an already failing test

This lint may soon be enforced in `package:pedantic`.

* Extend synthetic test timeout

Towards #1100 

Prepare for a world where we a reporter can be configured to write directly to a file.

* better solo

* Conditionally import coverage logic

Open to feedback on this. Here's how it works at the moment:

There's a new `--coverage` option that you can use to specify the output directory for your coverage. It will create a new output directory if one doesn't already exist.

The tests are run through the engine, and then get spit out to a coverage helper function. That coverage helper function:
**A)** Checks if it's a VM suite
**B)** Gathers coverage if it is
**C)** Outputs coverage to `${suite path}.vm.json`

So, for example, when I run:
```bash
pub run test --coverage hello_world test/vm/simple_repo_test.dart
```

A new file gets added at `hello_world/test/vm/simple_repo_test.dart.vm.json` with the coverage results!

Fixes #1082 

Also fix readme

Mark internal packages as deprecated to hopefully prevent accidental use.

* Update test to use analyzer 0.38.0

* Update test_core dep

* Add a dependency override for test_core

This had been used to detect feature support so that the package could
have a wider SDK constraint and have enhanced features for newer SDKs.
Drop the dependency and code checking the SDK version because:

- We now typically bump the SDK constraint rather than support multiple
  code paths.
- The remaining usage was for checking for DDC support in `pub serve`
  which doesn't exist anymore - we haven't yet deleted the tests or
  migrated them to use `build_runner serve`. This test and references to
  the old approach with both compilers is retained to make it clear what
  should be tested when we get around to migrating it.

pkg:vm_service_lib is discontinued

Related to https://github.com/dart-lang/vm_service_drivers/issues/257

* Depend on latest analyzer

* remove unnecessary quotes

* widen range

Since analyzer version 0.36.0, we no longer need to use elements2.
elements is equivalent.

Closes https://github.com/dart-lang/test/issues/1032

* Non-completed tests should cause failures

Added `backend.dart` files to `test_core` and `test_api` that expose some new classes for use with the new `parseMetadata` function.

- Don't surround versions with quotes unless they have a space.
- Remove the unnecessary lower bound for packages where the current
  lower bound is not resolvable due to SDK constraints.
- Change single quotes to double quotes since they are preferred in
  yaml.
- Remove version constraints from `test_api` to `test` and `test_core`
  since we will always have path overrides to those packages.

Version `1.7.0` adds the import so it's the minimum version required.
Allow versions through `2.x` since the breaking change will be to change
the import which will now be satisfied.

As part of implementing the "UI as code" feature
(https://github.com/dart-lang/language/blob/master/accepted/future-releases/unified-collections/feature-specification.md)
the analyzer is deprecating the following classes and methods:

- ForStatement and ForEachStatement (ForStatement2 is now used for
  both kinds of loops)

- ListLiteral.elements (use elements2, which has a more general return
  type)

- AstVisitor.visitForEachStatement and AstVisitor.visitForStatement
  (visitForStatement2 is now used for both kinds of loops)

- AstVisitor.visitMapLiteral and AstVisitor.visitSetLiteral
  (visitSetOrMapLiteral is now used for both kinds of literals).

See deprecation CL: https://dart-review.googlesource.com/c/sdk/+/95665/

After splitting the package the file was copied to some of the package
but missing from the `test_core` package. Move it back up the directory
structure so it is picked up for all sub-packages.

Fix lints that were not caught in `test_core` while this was missing.

This is a holdback from Dart 1 where some syntax or type errors were not
reported until runtime.