Rollup merge of #33832 - alexcrichton:android-memalign, r=luqmana

std: Use memalign, not posix_memalign, on Android

We've gotten requests to move our Android support as far back as API level 9
where unfortunately the `posix_memalign` API wasn't implemented yet. Thankfully,
however, the `memalign` API was and it appears to be usable with `free` on the
Android platform (see comments included in commit).

This should help fix some of the last few test failures when compiling against
API level 9.