Exclude flaky tests under Dr. Memory

TBR=zhaoqin@chromium.org
BUG=396172
NOTRY=true

Review URL: https://codereview.chromium.org/412623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284746 0039d316-1c4b-4281-b951-d872f2087c98

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

+# crbug.com/396172: flaky under Dr. Memory
+HeapTest.ThreadedWeakness

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

@@ -2,3 +2,5 @@
 LayerTreeHostAnimationTestNoBackgroundTickingWithoutActiveTree.RunSingleThread_DirectRenderer
 LayerTreeHostBlendingPixelTest.*
 LayerTreeHostFiltersPixelTest.*
+SchedulerTest.*
+LayerTreeHostTestContinuousPainting.*