cc: Added modifier string to clarify perf tests.

A few perf tests were writing results against the same measurement name making it impossible to distinguish and compare measurements. This patch adds modifier strings to make the measurments clear.

BUG=343684

Review URL: https://codereview.chromium.org/167753003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252118 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252118