Instead of instaling OCaml bindings in a location where installation
will not fail, don't build them in the first place.

Per code review feedback

Co-Authored-By: Mark Rousskov <mark.simulacrum@gmail.com>

…i-obk

[const-prop] Handle remaining MIR Rvalue cases

r? @oli-obk

Prefer statx on linux if available

This PR make `metadata`-related functions try to invoke `statx` first on Linux if available,
making `std::fs::Metadata::created` work on Linux with `statx` supported.

It follows the discussion in rust-lang#61386 , and will fix rust-lang#59743

The implementation of this PR is simply converting `struct statx` into `struct stat64` with
extra fields for `btime` if `statx` succeeds, since other fields are not currently used.

---

I also did a separated benchmark for `fs::metadata`, `stat64`, `statx`, and `statx` with conversion to `stat64`.
It shows that `statx` with conversion is even more faster than pure `statx`.
I think it's due to `sizeof stat64 == 114` but `sizeof statx == 256`.

Anyway, the bare implementation of `statx` with conversion is only about 0.2% slower than the original impl (`stat64`-family).
With heap-allocation counted (~8.5% of total cost), the difference between `stat` and `statx` (with or without conversion) is just nothing.

Therefore, I think it is not urgent to use bare `struct statx` as underlying representation now.
There is no need to break `std::os::linux::fs::MetadataExt::as_raw_stat` (rust-lang#61386 (comment))

[Separated bare benchmarks](https://gist.github.com/oxalica/c4073ecb202c599fe41b7f15f86dc79c):
```
metadata_ok             time:   [529.41 ns 529.77 ns 530.19 ns]
metadata_err            time:   [538.71 ns 539.39 ns 540.35 ns]
stat64_ok               time:   [484.32 ns 484.53 ns 484.75 ns]
stat64_err              time:   [481.77 ns 482.00 ns 482.24 ns]
statx_ok                time:   [488.07 ns 488.35 ns 488.62 ns]
statx_err               time:   [487.74 ns 488.00 ns 488.27 ns]
statx_cvt_ok            time:   [485.05 ns 485.28 ns 485.53 ns]
statx_cvt_err           time:   [485.23 ns 485.45 ns 485.67 ns]
```

r? @alexcrichton

Disable Go and OCaml bindings when building LLVM

Instead of instaling OCaml bindings in a location where installation
will not fail, don't build them in the first place.

…-E0575, r=kinnison

Add long error explanation for E0575

Part of rust-lang#61137.

…komatsakis

Add more coherence tests

I've wrote the missing test cases listed in [this google doc](https://docs.google.com/spreadsheets/d/1WlroTEXE6qxxGvEOhICkUpqguYZP9YOZEvnmEtSNtM0/edit#gid=0)

> The other thing that might be useful is to rename the existing tests so they all fit the new naming scheme we were using.

I'm not entirely sure how to do this. If everything from the google sheet is covered could I just remove the remaining tests in `src/test/ui/coherence` or is there something in there that should remain?

cc rust-lang#63599

r? @nikomatsakis

properly document panics in div_euclid and rem_euclid

For signed numbers, document that `div_euclid` and `rem_euclid` panic not just when `rhs` is 0, but also when the division overflows.

For unsigned numbers, document that `div_euclid` and `rem_euclid` panic when `rhs` is 0.

…r=simulacrum

add option to ping llvm ice-breakers to triagebot