[clang][utils] Modify make-ast-dump-check.sh to generate AST serialization dump tests
An AST serialization dump test is a test which compares the output of -ast-dump
on the source and of -ast-dump-all on a PCH generated from the source. Modulo
a few differences the outputs should match.
This patch to make-ast-dump-check.sh enables automatically generating
Differential Revision: https://reviews.llvm.org/D81786
Reviewed By: aaron.ballman, lebedev.ri