Improve soundness of rustc_arena#97711

Merged

bors merged 2 commits intorust-lang:masterfrom

Noratrieb:rustc-arena-ub

Jul 7, 2022

Commits on Jun 3, 2022

Adapt tests to be able to run in miri
Noratrieb
committed

Commits on Jul 6, 2022

Fix stacked borrows violation in rustc_arena
Noratrieb
committed