Auto merge of #122240 - RalfJung:miri-addr-reuse, r=oli-obk

miri: add some chance to reuse addresses of previously freed allocations

The hope is that this can help us find ABA issues.

Unfortunately this needs rustc changes so I can't easily run the regular benchmark suite. I used `src/tools/miri/tests/pass/float_nan.rs` as a substitute:
```
Before:
Benchmark 1: ./x.py run miri --stage 0 --args src/tools/miri/tests/pass/float_nan.rs --args --edition=2021
  Time (mean ± σ):      9.570 s ±  0.013 s    [User: 9.279 s, System: 0.290 s]
  Range (min … max):    9.561 s …  9.579 s    2 runs

After:
Benchmark 1: ./x.py run miri --stage 0 --args src/tools/miri/tests/pass/float_nan.rs --args --edition=2021
  Time (mean ± σ):      9.698 s ±  0.046 s    [User: 9.413 s, System: 0.279 s]
  Range (min … max):    9.666 s …  9.731 s    2 runs
```
That's a ~1.3% slowdown, which seems fine to me. I have seen a lot of noise in this style of benchmarking so I don't quite trust this anyway; we can make further experiments in the Miri repo after this migrated there.

r? `@oli-obk`

Author: bors