exclude test from cc_unittests on Dr.Memory bots

TBR=bruening@chromium.org
BUG=DR-i#1476

Review URL: https://codereview.chromium.org/394283003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283492 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/gtest_exclude/cc_unittests.gtest-drmemory_win32.txt

+# DR-i#1476
+LayerTreeHostAnimationTestNoBackgroundTickingWithoutActiveTree.RunSingleThread_DirectRenderer
+LayerTreeHostBlendingPixelTest.*
+LayerTreeHostFiltersPixelTest.*