Update ICU to 62.1 + local patches

What's new in ICU 62.1:
  - Unicode 11 (new scripts, Emoji update, Text Boundary/Line break updates)
  - CLDR 33.1 (locale data; http://cldr.unicode.org/index/downloads/cldr-33-1 )
  - More Numberformatter improvements and its support in MsgFormat
  - See http://site.icu-project.org/download/62 for more details.

The update steps are recorded in
  https://chromium.googlesource.com/chromium/deps/icu/+log/172d331..c28591b

The list of local changes are:

  Cherry-pick Greek lowercasing fix
  Fix a DecimalFormat maxSignificantDigits issue.

* Rebuild the data files: size eduction of ~ 45 KiB

   6386176 => 6340576 android
   4929248 => 4883232 cast
  10264208 => 10218000 common
   6372480 => 6326896 ios

* Update README.chromium and remove a reference to
  icudt.dll for Windows because it's not used any more.

* Drop patches that became unnecessary.

* Apply the remaining patches
   Isvalidenum.patch, locid_map.patch,
   double_conversion.patch

* Apply data-build related patches
  {wpo,vscomp,data.build,data.build.win,data_symb}.patch

* Apply BreakIterator related patches + locale1 patch

* Apply Google's patch for locale data
  - region display names
  - likely subtags
  - Arabic locale: default number system => Latn
  - AM/PM markers for Hindi and a few Indic locales

* Check in ICU 62.1 to the tree (62staging branch) by
  running scripts/update.sh.
  Build files are updated by the script.

TBR=drott@chromium.org
Bug: 850334
Test: None
Change-Id: I7327363c90b9bccda20c1be8f4a65399f36c4e99
Reviewed-on: https://chromium-review.googlesource.com/1128503


Reviewed-by: Jungshik Shin <jshin@chromium.org>