QMetaTypeCustomRegistry: use QHash::removeIf() instead of a custom erasing loop

Use QHash::removeIf() instead of a custom erasing loop on aliases
table when unregister custom type. It will still always detach even
if nothing needs to be removed, since QHash::removeIf() always detaches.
But this can potentially be fixed in the future, so it will be improved
indirectly.

Besides other things this also silences Clazy's "mixing iterators"
warning.

Change-Id: I3d6e8b0ed7dc10807570a0b0feac7eda6a0e572a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/kernel/qmetatype.cpp

@@ -150,13 +150,7 @@ struct QMetaTypeCustomRegistry
         auto &ti = registry[idx];
 
         // We must unregister all names.
-        auto it = aliases.begin();
-        while (it != aliases.end()) {
-            if (it.value() == ti)
-                it = aliases.erase(it);
-            else
-                ++it;
-        }
+        aliases.removeIf([ti] (const auto &kv) { return kv.value() == ti; });
 
         ti = nullptr;