Use fixed source code for parser context (#7717)

## Summary

The parser now uses the raw source code as global context and slices
into it to parse debug text. It turns out we were always passing in the
_old_ source code, so when code was fixed, we were making invalid
accesses. This PR modifies the call to use the _fixed_ source code,
which will always be consistent with the tokens.

Closes https://github.com/astral-sh/ruff/issues/7711.

## Test Plan

`cargo test`

crates/ruff_linter/src/test.rs

@@ -197,7 +197,7 @@ pub(crate) fn test_contents<'a>(
                 &directives,
                 settings,
                 flags::Noqa::Enabled,
-                source_kind,
+                &transformed,
                 source_type,
             );