[clang] [llvm] [memprof] Add memprof options as a clang frontend flag (PR #128615)

[Teresa Johnson via cfe-commits]

https://github.com/teresajohnson commented:

Not opposed to adding this as a clang driver flag especially if it is needed for something other than testing/debugging, however, you could presumably always add the exported symbol when -fmemory-profiler is specified (or does the linker give an error if the specified symbol doesn't exist?).

Couple small suggestions below.

https://github.com/llvm/llvm-project/pull/128615