Add a Mac Valgrind suppression for an invalid free deep in the NIB loading procedure.

tools/valgrind/memcheck/suppressions_mac.txt

Index: tools/valgrind/memcheck/suppressions_mac.txt
diff --git a/tools/valgrind/memcheck/suppressions_mac.txt b/tools/valgrind/memcheck/suppressions_mac.txt
index 839ad0150ae09068e45edc5e42112a232200f58e..5e6920fedcf7298b4515843a39184122649a230b 100644
--- a/tools/valgrind/memcheck/suppressions_mac.txt
+++ b/tools/valgrind/memcheck/suppressions_mac.txt
@@ -165,6 +165,24 @@
    fun:CFArrayCreateMutableCopy
    fun:_ZN8Security12KeychainCore5Trust8evaluateEv
 }
+{
+   bug_32564
+   Memcheck:Free
+   fun:free
+   fun:_cache_free_block
+   fun:_cache_collect_free
+   fun:_cache_fill
+   fun:_cache_addForwardEntry
+   fun:class_respondsToSelector
+   fun:-[NSNibOutletConnector establishConnection]
+   fun:-[NSIBObjectData nibInstantiateWithOwner:topLevelObjects:]
+   fun:loadNib
+   fun:+[NSBundle(NSNibLoading) _loadNibFile:nameTable:withZone:ownerBundle:]
+   fun:+[NSBundle(NSNibLoading) loadNibFile:externalNameTable:withZone:]
+   fun:-[NSWindowController loadWindow]
+   fun:-[NSWindowController window]
+   fun:_ZN12_GLOBAL__N_155EditSearchEngineControllerTest_ValidImageOriginals_Test8TestBodyEv
+}
 
 # 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.