Rollup merge of #78524 - tmiasko:source-files-borrow, r=Aaron1011

Avoid BorrowMutError with RUSTC_LOG=debug

```console
$ touch empty.rs
$ env RUSTC_LOG=debug rustc +stage1 --crate-type=lib empty.rs
```

Fails with a `BorrowMutError` because source map files are already
borrowed while `features_query` attempts to format a log message
containing a span.

Release the borrow before the query to avoid the issue.

1 files changed, 5 insertions, 0 deletions

diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index d85558ea2f5..666e5d402ef 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1775,6 +1775,11 @@ impl<'test> TestCx<'test> {
         let mut aux_rustc =
             aux_cx.make_compile_args(input_file, aux_output, EmitMetadata::No, AllowUnused::No);
 
+        for key in &aux_props.unset_rustc_env {
+            aux_rustc.env_remove(key);
+        }
+        aux_rustc.envs(aux_props.rustc_env.clone());
+
         let (dylib, crate_type) = if aux_props.no_prefer_dynamic {
             (true, None)
         } else if self.config.target.contains("cloudabi")