Mmap fix on system with 64k pagesize. (#59695)
Not sure if this is the best approach but seemed to allow Mmap test to
pass. Seems the pagesize was being set to value at build-time rather
than being re-evaluated at runtime. Running Mmap tests on system with
64k pagesize, Mmap would still think its on a system with 4k pagesize
and therefore fail.
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Co-authored-by: Jameson Nash <vtjnash@gmail.com>
