[compiler-rt] [Sanitizers][Apple] Fix logic bugs that break RestrictMemoryToMaxAddress (PR #124712)

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thetruestblue wrote:

> @thetruestblue I think it would be good to also explain a little in the commit message how this ended up working. The current description makes it sound like this never worked which I'm pretty sure isn't the case.

I only have a hypothesis for why this worked in the past, but don't have the historical experience to explain it. This code has been changed many times. I have a theory that we the expectation that any space beyond max address used to return invalid, but now that value is not returned unless we surpass the expand vm space available to some processes. I will add that to the commit message. But you are right, I do believe this worked in the past. 

https://github.com/llvm/llvm-project/pull/124712