[Backend] Keep call site info valid through the backend
Handle call instruction replacements and deletions in order to preserve
valid state of the call site info of the MachineFunction.
([10/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <firstname.lastname@example.org>
Co-authored-by: Nikola Prica <email@example.com>
Co-authored-by: Ivan Baev <firstname.lastname@example.org>
Differential Revision: https://reviews.llvm.org/D61062