Fixes memory leak

tools/valgrind/memcheck/suppressions_mac.txt

 # There are three kinds of suppressions in this file:
 # 1. Third party stuff we have no control over.
 #
 # 2. Intentional unit test errors, stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing.
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system.
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 2427 matching lines @@
    fun:_ZN3gfx30VideoDecodeAccelerationSupport6CreateEiiiPKvm
    fun:_ZN3gfx46VideoDecodeAccelerationSupportTest_Create_Test8TestBodyEv
 }
 {
    bug_131361
    Memcheck:Overlap
    fun:memcpy
    ...
    fun:_ZN2v88internal18GvnBasicBlockState32*
 }
-{
-   bug_132231
-   Memcheck:Leak
-   fun:calloc
-   fun:_internal_class_createInstanceFromZone
-   fun:_internal_class_createInstance
-   fun:+[NSObject(NSObject) allocWithZone:]
-   fun:+[NSObject(NSObject) alloc]
-   fun:_ZN12_GLOBAL__N_112ImageMacTest20CreateBitmapImageRepEiiPP16NSBitmapImageRep
-}