Add mechanism to check for invalid sized frees

[ronawho]

Spawned off from #13611 (comment)

Our array allocation sub-interface requires the allocation size when free'ing:

chapel/runtime/include/chpl-mem-array.h

Lines 102 to 104 in a1cc8ea

	void chpl_mem_array_free(void* p,
	size_t nmemb, size_t eltSize,
	int32_t lineno, int32_t filename) {

We do this so we can figure out if we've allocated memory through the comm layer, or through the normal memory interface. Passing in the wrong size to the free routine can result in mixed allocation calls, which is UB and can cause bugs like: #13611

We should add the ability to check if the free size matches the allocation size. Note that this requires storing the sizes of allocations, so we don't want to do this by default, but that's something we already track for --memTrack so we can probably add that as a sanity check there pretty easily.

[ronawho]

This ended being pretty straightforward. I have a prototype branch at https://github.com/ronawho/chapel/tree/check-sized-dealloc, and I'll try to PR that this week.

[ronawho]

See #15918 (comment) for additional motivation.

[ronawho]

We should do these checks for the realloc path too.