Suppress a Valgrind error and disable a test under HeapChecker.

BUG=315883, 319242
TBR=oshima@chromium.org

Review URL: https://codereview.chromium.org/72713002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235129 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235129