Undo the recent stress changes to the context loss test.

The underlying infrastructure isn't ready for this to crash the GPU
process 30 times in a row. Change back to running this test once to
address continued flakiness on the bots.

BUG=365904
NOTRY=true
TBR=bajones@chromium.org

Review URL: https://codereview.chromium.org/252793003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266315 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed