valgrind: add suppression for image decoder test leaks
valgrind: add suppression for image decoder test leaks

BUG=37727
TEST=tools/valgrind/chrome_tests.sh -t test_shell --gtest_filter=BMPImageDecoderTest.DecodingFast:ICOImageDecoderTest.Decoding:ICOImageDecoderTest.ImageNonZeroFrameIndex

Review URL: http://codereview.chromium.org/690001

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@40983 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser