Valgrind: Disable failing TouchExplorationTest.TwoFingerTouch test.

BUG=370168
NOTRY=true
TBR=mfomitchev@chromium.org

Review URL: https://codereview.chromium.org/266723017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@268316 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/gtest_exclude/ui_unittests.gtest-memcheck.txt

 # http://crbug.com/222606
 RenderTextTest.DisplayRectShowsCursorLTR
+
+# http://crbug.com/370168
+TouchExplorationTest.TwoFingerTouch