Devirtualize a call on alloca without waiting for post inline cleanup and next...

Devirtualize a call on alloca without waiting for post inline cleanup and next DevirtSCCRepeatedPass iteration.

This aims to fix a missed inlining case.

If there's a virtual call in the callee on an alloca (stack allocated object) in
the caller, and the callee is inlined into the caller, the post-inline cleanup
would devirtualize the virtual call, but if the next iteration of
DevirtSCCRepeatedPass doesn't happen (under the new pass manager), which is
based on a heuristic to determine whether to reiterate, we may miss inlining the
devirtualized call.

This enables inlining in clang/test/CodeGenCXX/member-function-pointer-calls.cpp.

This is a second commit after a revert
https://reviews.llvm.org/rG4569b3a86f8a4b1b8ad28fe2321f936f9d7ffd43 and a fix
https://reviews.llvm.org/rG41e06ae7ba91.

Differential Revision: https://reviews.llvm.org/D69591