[compiler-rt] mmapForContinuousMode: Align Linux's impl to __APPLE__'s more. NFC. (PR #95702)

[NAKAMURA Takumi via llvm-commits]

chapuni wrote:

> Why?

"I want to introduce bitmap bias w/o posting RFC."

Rather than appending similar changes (but with different variables) into __linux__ impl, I think it'd be better to align blocks with same variable for possible commonization in the future. It can also make simpler to explain the difference of bitmap between __APPLE__ and bias mode.

To introduce bitmap in biased continuous mode, the bias for counters cannot be reused since the layout of `__llvm_prf_bits` and `__llvm_prf_cnts` is different from `profraw`.

I thought actual commonization would be too early since it would be intrusive.



https://github.com/llvm/llvm-project/pull/95702