Truncate huge gtest output snippets in the annotator
Truncate huge gtest output snippets in the annotator

This avoids flooding the logs with lots of data that gums up
the infrastructure.

Note that the summary uploaded to Google Storage contains
full test output for debugging.

Also note src-side change https://codereview.chromium.org/324893004/
- we need build-side protection as well though.

BUG=382648

Review URL: https://codereview.chromium.org/321113004

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@276637 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build