Change PTransformOverride.get_matcher() to PTransformOverride.matches(AppliedTransform)

[kennknowles]

This will simplify the interface.

PTransformOverride.matches() should be a efficient check to  determine if a given transform should be replaced while PTransformOverride.get_replacement_transform() should generate and return the actual replacement.

Imported from Jira BEAM-3614. Original Jira may contain additional context.
Reported by: chamikara.