shard Dr.Memory content_browsertests more in the bot
shard Dr.Memory content_browsertests more in the bot

Dr.Memory content_browsertests bots always timeout at the end of execution,
which might be caused by too many tests.
We split tests into more shards to see if it can imporove the situation.

R=bruening@chromium.org, thakis@chromium.org
BUG=NONE
NOTRY=true

Review URL: https://codereview.chromium.org/255233003

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@267632 0039d316-1c4b-4281-b951-d872f2087c98

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