Merge `CompilerError::CompilationFailed` and `CompilerError::ICE`.
`CompilerError` has `CompilationFailed` and `ICE` variants, which seems reasonable at first. But the way it identifies them is flawed:
- If compilation errors out, i.e. `RunCompiler::run` returns an `Err`, it uses `CompilationFailed`, which is reasonable.
- If compilation panics with `FatalError`, it catches the panic and uses `ICE`. This is sometimes right, because ICEs do cause `FatalError` panics, but sometimes wrong, because certain compiler errors also cause `FatalError` panics. (The compiler/rustdoc/clippy/whatever just catches the `FatalError` with `catch_with_exit_code` in `main`.)
In other words, certain non-ICE compilation failures get miscategorized as ICEs. It's not possible to reliably distinguish the two cases, so this commit merges them. It also renames the combined variant as just `Failed`, to better match the existing `Interrupted` and `Skipped` variants.
Here is an example of a non-ICE failure that causes a `FatalError` panic, from `tests/ui/recursion_limit/issue-105700.rs`:
```
#![recursion_limit="4"]
#![invalid_attribute]
#![invalid_attribute]
#![invalid_attribute]
#![invalid_attribute]
#![invalid_attribute]
//~^ERROR recursion limit reached while expanding
fn main() {{}}
```
r? ``@spastorino``
328a5b7719