Removing valgrind suppression for crbug.com/446256

TBR=earthdok@chromium.org
NOTRY=true
BUG=446256

Review URL: https://codereview.chromium.org/900653002

Cr-Commit-Position: refs/heads/master@{#314349}

tools/valgrind/drmemory/suppressions_full.txt

@@ -1889,11 +1889,6 @@ name=bug_436131_c
 *!ash::test::ShelfViewTest_OverflowBubbleSize_Test::TestBody
 *!testing::internal::HandleExceptionsInMethodIfSupported<>
 
-UNINITIALIZED READ
-name=bug_446256
-*!`anonymous namespace'::GraphicsContextTest_trackDisplayListRecording_Test::TestBody
-*!testing::internal::HandleExceptionsInMethodIfSupported<>
-
 UNINITIALIZED READ
 name=bug_399842
 skia.dll!S32A_Opaque_BlitRow32_SSE4