Widen a Mac UI valgrind suppression sligthly

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 # running overnight and removing outdated bugs/suppressions.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 309 matching lines @@
    fun:sqlite3MemMalloc
    ...
    fun:yy_reduce
    fun:sqlite3Parser
    ...
    fun:_ZN7history15HistoryDatabase4InitERK8FilePathS3_
 }
 {
    bug_25656
    Memcheck:Addr4
+   ...
    fun:bestBtreeIndex
    fun:sqlite3WhereBegin
    fun:sqlite3Select
    fun:yy_reduce
    fun:sqlite3Parser
    ...
    fun:_ZN7history14HistoryBackend*
 }
 {
    bug_25661
    Memcheck:Addr4
    fun:_ZNK10scoped_ptrI11ChildThreadE3getEv
    fun:_ZN12ChildProcess11main_threadEv
    fun:_ZN11ChildThread7currentEv
    fun:_ZN25WebMessagePortChannelImpl11postMessageERKN6WebKit9WebStringEPNS0_9WebVectorIPNS0_21WebMessagePortChannelEEE
    fun:_ZN7WebCore26PlatformMessagePortChannel19postMessageToRemoteEN3WTF10PassOwnPtrINS_18MessagePortChannel9EventDataEEE
    fun:_ZN7WebCore18MessagePortChannel19postMessageToRemoteEN3WTF10PassOwnPtrINS0_9EventDataEEE
    fun:_ZN7WebCore11MessagePort11postMessageEN3WTF10PassRefPtrINS_21SerializedScriptValueEEEPKNS1_6VectorINS1_6RefPtrIS0_EELm1EEERi
    fun:_ZN7WebCore8V8Custom32v8MessagePortPostMessageCallbackERKN2v89ArgumentsE
    fun:_ZN2v88internalL21Builtin_HandleApiCallENS0_9ArgumentsE
 }