Reland "[scudo] resize stack depot for allocation ring buffer" (#81028)

First commit of the stack is a clean reland, second is  the fix.

There was a typo in the `static_assert` that meant we were asserting the
size of the pointer, not the struct.

Also changed `alignas` to be more intuitive, but that is NFC.

Ran builds in Android here: https://r.android.com/2954411