Rename MultisampledRenderToTextureTest to fit existing heapcheck exclusion filter.

BUG=318881,259393
TBR=earthdok@chromium.org

Review URL: https://codereview.chromium.org/68523008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234879 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234879