Create per-revision mir_dump_dir

Author: ChrisDenton

src/tools/compiletest/src/runtest.rs

@@ -1399,7 +1399,12 @@ impl<'test> TestCx<'test> {
         let mut mir_dump_dir = self.config.build_test_suite_root.clone();
         debug!("input_file: {}", self.testpaths.file);
         mir_dump_dir.push(&self.testpaths.relative_dir);
-        mir_dump_dir.push(self.testpaths.file.file_stem().unwrap());
+        let name = self.testpaths.file.file_stem().unwrap();
+        if let Some(revision) = self.revision {
+            mir_dump_dir.push(format!("{name}#{revision}"));
+        } else {
+            mir_dump_dir.push(name);
+        }
         mir_dump_dir
     }