[CFI] Expand blacklisted entries

Blacklist two functions that can call casted function pointers, there is
not an easy way to fix these failures yet.

BUG=v8:7164

Change-Id: I895ccb09359d38c95c1ff93e41c306ecb1ad57fc
Reviewed-on: https://chromium-review.googlesource.com/1003226Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52539}

tools/cfi/blacklist.txt

@@ -19,3 +19,8 @@ src:*src/api-arguments-inl.h
 
 # v8 callback that casts argument template parameters
 fun:*PendingPhantomCallback*Invoke*
+
+# weak_callback_ is cast from original type.
+fun:*GlobalHandles*PostGarbageCollectionProcessing*
+
+fun:*InvokeAccessorGetterCallback*