[Android] Move content_browsertests to main waterfall/trybots.

It's passing consistently on android_fyi_dbg trybots and on FYI waterfall bots running ICS.

BUG=270144
NOTRY=True

Review URL: https://chromiumcodereview.appspot.com/22299007

git-svn-id: http://src.chromium.org/svn/trunk/src/build@216442 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

android/pylib/gtest/gtest_config.py

@@ -6,7 +6,6 @@
 
 # Add new suites here before upgrading them to the stable list below.
 EXPERIMENTAL_TEST_SUITES = [
-    'content_browsertests',
 ]
 
 # Do not modify this list without approval of an android owner.
@@ -30,4 +29,5 @@ STABLE_TEST_SUITES = [
     'webkit_unit_tests',
     'breakpad_unittests',
     'sandbox_linux_unittests',
+    'content_browsertests',
 ]