pdl: refactor “isinstance(…) or isinstance(…)”

Python lets you check for multiple types with a single call.

Test: atest pdl_python_generator_test
(cherry picked from https://android-review.googlesource.com/q/commit:818252464e3895abb7e50b1a5ad499ffa35a39e7)
Merged-In: I140fe9b3cf57a0e5f3f72c5957e892c6b3aaffcd
Change-Id: I140fe9b3cf57a0e5f3f72c5957e892c6b3aaffcd