Auto merge of #127288 - lqd:typelen-cache, r=compiler-errors

cache type sizes in type-size limit visitor

This is basically rust-lang/rust#125507 (comment) as lcnr can't open the PR now.

Locally it reduces the `itertools` regression by quite a bit, to "only +50%" compared to nightly (that includes overhead from the local lack of artifact post-processing, and is just a data point to compare to the 10-20x timings without the cache).

```console
Benchmark 1: cargo +stage1 build --release
  Time (mean ± σ):      2.721 s ±  0.009 s    [User: 2.446 s, System: 0.325 s]
  Range (min … max):    2.710 s …  2.738 s    10 runs

Benchmark 2: cargo +nightly build --release
  Time (mean ± σ):      1.784 s ±  0.005 s    [User: 1.540 s, System: 0.279 s]
  Range (min … max):    1.778 s …  1.792 s    10 runs

Summary
  cargo +nightly build --release ran
    1.52 ± 0.01 times faster than cargo +stage1 build --release
```

On master, it's from 34s to the 2.7s above.

r? compiler-errors

Author: bors