Co-authored-by: varkor <github@varkor.com>

Co-authored-by: hafiz <20735482+ayazhafiz@users.noreply.github.com>

Some tests (e.g. ui-fulldeps/create-dir-all-bare.rs) assume that
RUST_TEST_TMPDIR exists on the system running the test. Expand
remote-test-{server,client} such that a tmp directory is created on the
remote runner and this environment variable will point at it.

There was an unused verbose command line argument. Add some prints if
verbose is set.

Allow tests to use
// ignore-remote
to ignore the test when using remote-test-{client,server}. In most
situations this would be covered by
// ignore-cross-compile
but I see no reason that a non-cross compiled remote test runner
shouldn't work.

…Simulacrum

Remote testing fixes

Improvements for remote testing

- Create a `RUST_TEST_TMPDIR` directory on the remote testing host
- Verbose mode for remote-test-server
- Skip tests which don't support remote testing using `// ignore-remote`

To test:
- Build `remote-test-server` for the target machine and copy it over
- On the target:
``` sh
remote-test-server remote
```
- On the build machine
``` sh
export TEST_DEVICE_ADDR="1.2.3.4:12345"
./x.py test
```

… r=oli-obk

InstCombine: Don't optimize `&mut *x` into `x`

Fixes rust-lang#72797

Correct generic parameter ordering in error note for E0747

Fixes rust-lang#72815.

r? @varkor

Add a test to ensure Fuse stays covariant

When rust-lang#70502 attempted to specialize the data types in `Fuse`, one of the problems we found was that it broke variance. This was also realized when `Fuse` was first added, rust-lang#35656 (diff), but now this PR adds a test so we don't forget again.

Add assert to Vec with_capacity docs