Auto merge of #116692 - Nadrieril:half-open-ranges, r=cjgillot

Match usize/isize exhaustively with half-open ranges

The long-awaited finale to the saga of [exhaustiveness checking for integers](rust-lang/rust#50912)!

```rust
match 0usize {
    0.. => {} // exhaustive!
}
match 0usize {
    0..usize::MAX => {} // helpful error message!
}
```

Features:
- Half-open ranges behave as expected for `usize`/`isize`;
- Trying to use `0..usize::MAX` will tell you that `usize::MAX..` is missing and explain why. No more unhelpful "`_` is missing";
- Everything else stays the same.

This should unblock rust-lang/rust#37854.

Review-wise:
- I recommend looking commit-by-commit;
- This regresses perf because of the added complexity in `IntRange`; hopefully not too much;
- I measured each `#[inline]`, they all help a bit with the perf regression (tho I don't get why);
- I did not touch MIR building; I expect there's an easy PR there that would skip unnecessary comparisons when the range is half-open.

Author: bors