In trying to fuzz test a different issue, I ran into a reproducible case where
we end up with a broken handlescope stack. The issue requires a large number
of handlescopes created with aggressive GC, so hopefully it isn't something
that too many users have run into.
The issue is that a single HandleScope address is used to initialize two
HandleScopes. The fix could just be to create a 2nd HS variable (to get a 2nd
address), but the first initialization is unnecessary and can just be removed.
(Note that EventManager dispatch creates its own HandleScope, so the one
removed in frameCompletedLoading really did nothing)