AST Compare tests libpypa vs cpython

@kmod 
I have implemented a priliminary patch for the suggested check.
It already shows some issues. I will check them out and fix them.
Hmm this change breaks for me and I'm not sure I can get -ltinfo from apt in my ubuntu.  Is it actually needed?  It looks like you're using the LLVM_LDFLAGS which will include this dependency.