Cherry pick 3 patches from the upstream

* Fix the undefined behavior in decimal number parsing

      http://bugs.icu-project.org/trac/changeset/40950

* Fix the handling of non-BMP characters in CJK breakiterator

      http://www.icu-project.org/trac/changeset/40949

* Limit the recursion depth of UnicodeSet pattern

      http://bugs.icu-project.org/trac/changeset/40979

TBR=inferno@chromium.org
Bug: chromium:799850, chromium:796807, chromium:796752
Test: See the bugs.
Change-Id: I1a8909371b601f36faca911039b10d36c7a92c85
Reviewed-on: https://chromium-review.googlesource.com/1009001


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