[InferAddressSpaces] Handle the pair of ptrtoint/inttoptr.
- ptrtoint and inttoptr are defined as no-op casts if the integer value as the same size as the pointer value. The pair of ptrtoint/inttoptr is in fact a no-op cast sequence between different address spaces. Teach infer-address-spaces to handle them like a bitcast.
Reviewers: arsenm, chandlerc
Subscribers: jvesely, wdng, nhaehnle, hiraditya, kerbowa, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D81938