Roll src/third_party/icu/ faee8bc70..2ecd66c69 (3 commits)

https://chromium.googlesource.com/chromium/deps/icu.git/+log/faee8bc70570..2ecd66c696c4

$ git log faee8bc70..2ecd66c69 --date=short --no-merges --format='%ad %ae %s'
2019-09-12 thakis Remove a few TODO(GYP)s that look obsolete.
2019-08-29 jose.dapena Cherry-pick "Do not override clang compiler internal builtins" in ICU
2019-08-30 jose.dapena Cherry-pick "Remove obsolete U_HAVE_STD_ATOMICS and similar @internal macros." in ICU

Created with:
  roll-dep src/third_party/icu

TBR=jshin

Bug: 819294
Change-Id: I764954ad1d8675d3b614b120fdbb1fe2e607b946
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1810797Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#697605}

DEPS

@@ -1038,7 +1038,7 @@ deps = {
     Var('chromium_git') + '/chromium/deps/hunspell_dictionaries.git' + '@' + '681ca92480ecc11d35feae8c1c00e4e035630f43',
 
   'src/third_party/icu':
-    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + 'faee8bc70570192d82d2978a71e2a615788597d1',
+    Var('chromium_git') + '/chromium/deps/icu.git' + '@' + '2ecd66c696c46e255cd634d3175b1072f4499949',
 
   'src/third_party/icu4j': {
       'packages': [