gstvalue: Avoid expensive fallback on intersection
The type checks at the end of gst_value_intersect
to call the flagset
intersection are relatively expensive.
If we already know that:
- There was a compare function but it didn't return GST_VALUE_EQUAL
- AND none of the registered intersect functions failed
Then we know they can't intersect and can return early.
Trims ~20% of the instruction calls