Rollup merge of #95352 - jyn514:full-relative-path, r=Mark-Simulacrum

Rollup merge of #95352 - jyn514:full-relative-path, r=Mark-Simulacrum

[bootstrap] Print the full relative path to failed tests

Before:
```
failures:
    [ui] rustdoc-ui/intra-doc/feature-gate-intra-doc-pointers.rs

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 163 filtered out; finished in 0.45s
```

After:
```
failures:
    [ui] src/test/rustdoc-ui/intra-doc/feature-gate-intra-doc-pointers.rs

test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 163 filtered out; finished in 0.45s
```

This allows copy pasting the path or using Ctrl+Click in IDEs to go directly to the file, instead of having to edit the filename first.