Suppress an unaddressable access in HarfBuzzShaper.

TBR=eae@chromium.org
BUG=480650

Review URL: https://codereview.chromium.org/1100423002

Cr-Commit-Position: refs/heads/master@{#326677}

tools/valgrind/drmemory/suppressions.txt

@@ -774,3 +774,10 @@ name=http://crbug.com/476586b
 *!cc::LayerTreeHost::BeginMainFrame
 *!cc::ThreadProxy::BeginMainFrame
 *!base::internal::InvokeHelper<>::MakeItSo
+
+UNADDRESSABLE ACCESS
+name=https://crbug.com/480650
+wtf.dll!WTF::String::make16BitFrom8BitSource
+blink_platform.dll!blink::normalizeCharacters
+blink_platform.dll!blink::HarfBuzzShaper::HarfBuzzShaper
+*!`anonymous namespace'::HarfBuzzShaperTest*