[MemSheriff] Widen a DrMemory suppression.

BUG=266484
TBR=mcasas@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/554323002

Cr-Commit-Position: refs/heads/master@{#293955}

tools/valgrind/drmemory/suppressions.txt

@@ -420,7 +420,7 @@ ntdll.dll!RtlExitUserThread
 GDI USAGE ERROR
 name=http://crbug.com/266484
 skia.dll!HDCOffscreen::draw
-skia.dll!SkScalerContext_GDI::generateImage
+...
 skia.dll!SkScalerContext::getImage
 skia.dll!SkGlyphCache::findImage
 skia.dll!D1G_RectClip