[clang] [profile] Add a clang option -fprofile-continuous that enables continuous instrumentation profiling mode (PR #124353)

[Tobias Hieta via cfe-commits]

tru wrote:

Just saw this in LLVM weekly. But this is not supported on Windows right? Only the UNIX platforms that can mmap? In that case it the limitation needs to be documented   

https://github.com/llvm/llvm-project/pull/124353