Rollup merge of #78705 - Mark-Simulacrum:nicer-failure-compiletest, r=jyn514

Print a summary of which test suite failed

Especially on CI, where cross-compiling is common and single builder may end up
with multiple hosts and multiple targets, it can be annoying to scroll back to
the nearest start of test marker. This prints out a summary of the test suite
being run directly in compiletest.

For example, on a mir-opt failure, this would show something like this:

```
failures:
    [mir-opt] mir-opt/while-storage.rs

test result: FAILED. 140 passed; 1 failed; 2 ignored; 0 measured; 0 filtered out

Some tests failed in compiletest suite=mir-opt mode=mir-opt host=x86_64-unknown-linux-gnu target=x86_64-unknown-linux-gnu
```

Fixes #78517

0 files changed, 0 insertions, 0 deletions