[clang] Add cc1 option -fctor-dtor-return-this

This option forces constructors and non-deleting destructors to return
`this` pointer in C++ ABI (except for Microsoft ABI, on which this flag
has no effect).

This is similar to ARM32, Apple ARM64, or Fuchsia C++ ABI, but can be
applied to any target triple.

Differential Revision: https://reviews.llvm.org/D119209