Some `build-fail`s are wrongly treated as `test-fail`s.

[kennytm]

From the most recent cargobomb report at rust-lang/rust#44287, the following should be considered build-fail, but are shown as test-fail:

• generator-0.5.0 failed to build an example.
• treeflection_derive-0.1.16, ditto.
• whiteread-0.4.3 failed to build a doctest.

[est31]

@kennytm i guess that's because "build-fail" means cargo build failed, and "test-fail" means cargo test failed. Examples/doctests/integration tests and most other tests are #[cfg(test)] so not compiled when doing cargo build. Why should these cases be treated differently from how cargo treats them?

[kennytm]

@est31 I'd expect "build fail" means error in compilation, while "test fail" means error in runtime.