Auto merge of #31887 - SimonSapin:quiet-test, r=alexcrichton

Shorter output for `rustc --test` binaries.

Until now, a program created with `rustc --test` prints at least one line per test. This can be very verbose, especially with [data-driven tests](https://internals.rust-lang.org/t/test-and-external-test-harnesses/3145) when hundreds or thousands of tests is not rare.

This changes the default output to one character per test (except metrics and benchmarks results which have additional data to show):

```
     Running target/debug/wpt-75c594dc1e6e6187

running 314 tests
..............................................................................
..............................................................................
..............................................................................
..............................................................................
..
test result: ok. 314 passed; 0 failed; 0 ignored; 0 measured
```

<s>The previous behavior is available by passing `--verbose` to the test program. Maybe `cargo test --verbose` could be changed to do that?</s> **Edit:** the default is now unchanged, `-q` or `--quiet` enables the new output.

0 files changed, 0 insertions, 0 deletions