[suspend] Wrap mmap and unmmap around critical sections to better handle library...

[suspend] Wrap mmap and unmmap around critical sections to better handle library interposing. Fixes #19379

Instruments uses library interposing to record calls to mmap and munmap. It does take lock within the interposers
which means the async suspend could suspend a thread holding such lock while sgen tries to mmap more memory in,
causing a deadlock.

The workaround is to protect our uses of mmap and munmap in the hopes that they are enough to reduce the likelihood
of those hangs happening.