pdl: Delete the python implementation of a PDL parser

This implementation no longer has a use case now that the
python cxx generator is available as replacement for the
legacy generator.

Test: NA
(cherry picked from https://android-review.googlesource.com/q/commit:3307b8e1177c7d58089296902d8e6fa5c995b105)
Merged-In: I4b0aecd3622f1c6828c04bc1432a13cbda6a6c61
Change-Id: I4b0aecd3622f1c6828c04bc1432a13cbda6a6c61