[MemSheriff] Widen existing suppression.

The very first invocation of [NSCursor push]/[NSCursor set] leaks,
intentionally. Suppress all invocations for now. ([NSCursor set] only
in the suppressions, seems -push seems to get inlined.

BUG=257276, 379331
TBR=thestig@chromium.org, shess@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/303123009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@273917 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/memcheck/suppressions_mac.txt

@@ -112,14 +112,7 @@
    bug_257276_b
    Memcheck:Leak
    fun:malloc_zone_malloc
-   fun:_CFRuntimeCreateInstance
-   fun:CFNumberCreate
-   fun:get_colorspace
-   fun:initImagePng
-   fun:_CGImagePluginInitPNG
-   fun:makeImagePlus
-   fun:CGImageSourceCreateImageAtIndex
-   fun:CGImageCreateWithPNGDataProvider
+   ...
    fun:setCursorFromBundle
    fun:CoreCursorSet
    fun:-[NSCursor set]