Speed up QObject::connect with function pointers

When resolving the signal/slot of connect(&Foo::bar, ...) we place a meta-call
to map the address to the method index. Once we have found the index, we don't
need to continue but can return the result right away.

Change-Id: I67bb22df394d7c22dc1731367c0961b958ed77b3
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

src/tools/moc/generator.cpp

@@ -1254,6 +1254,7 @@ void Generator::generateStaticMetacall()
             fprintf(out, "            if (*reinterpret_cast<_t *>(func) == static_cast<_t>(&%s::%s)) {\n",
                     cdef->classname.constData(), f.name.constData());
             fprintf(out, "                *result = %d;\n", methodindex);
+            fprintf(out, "                return;\n");
             fprintf(out, "            }\n        }\n");
         }
         if (!anythingUsed)