Rollup merge of #129640 - saethlin:unignore-android-in-alloc, r=tgross35

Re-enable android tests/benches in alloc/core

This is basically a revert of rust-lang/rust#73729. These tests better work on android now; it's been 4 years and we don't use dlmalloc on that target anymore.

And I've validated that they should pass now with a try-build :)