Extract loading and comparison of compiletest outputs to new fn

Moved into ```fn load_compare_outputs(&self, proc_res: &ProcRes, explicit_format: bool) -> usize```

src/tools/compiletest/src/runtest.rs

@@ -2934,44 +2934,49 @@ impl<'test> TestCx<'test> {
         }
     }
 
-    fn run_ui_test(&self) {
-        // if the user specified a format in the ui test
-        // print the output to the stderr file, otherwise extract
-        // the rendered error messages from json and print them
-        let explicit = self
-            .props
-            .compile_flags
-            .iter()
-            .any(|s| s.contains("--error-format"));
-        let proc_res = self.compile_test();
-        self.check_if_test_should_compile(&proc_res);
-
+    fn load_compare_outputs(&self, proc_res: &ProcRes, explicit_format: bool) -> usize {
         let expected_stderr = self.load_expected_output(UI_STDERR);
         let expected_stdout = self.load_expected_output(UI_STDOUT);
-        let expected_fixed = self.load_expected_output(UI_FIXED);
 
         let normalized_stdout =
             self.normalize_output(&proc_res.stdout, &self.props.normalize_stdout);
 
-        let stderr = if explicit {
+        let stderr = if explicit_format {
             proc_res.stderr.clone()
         } else {
             json::extract_rendered(&proc_res.stderr)
         };
 
         let normalized_stderr = self.normalize_output(&stderr, &self.props.normalize_stderr);
-
         let mut errors = 0;
         if !self.props.dont_check_compiler_stdout {
             errors += self.compare_output("stdout", &normalized_stdout, &expected_stdout);
         }
         if !self.props.dont_check_compiler_stderr {
             errors += self.compare_output("stderr", &normalized_stderr, &expected_stderr);
         }
+        errors
+    }
+
+    fn run_ui_test(&self) {
+        // if the user specified a format in the ui test
+        // print the output to the stderr file, otherwise extract
+        // the rendered error messages from json and print them
+        let explicit = self
+            .props
+            .compile_flags
+            .iter()
+            .any(|s| s.contains("--error-format"));
+        let proc_res = self.compile_test();
+        self.check_if_test_should_compile(&proc_res);
+
+        let expected_fixed = self.load_expected_output(UI_FIXED);
 
         let modes_to_prune = vec![CompareMode::Nll];
         self.prune_duplicate_outputs(&modes_to_prune);
 
+        let mut errors = self.load_compare_outputs(&proc_res, explicit);
+
         if self.config.compare_mode.is_some() {
             // don't test rustfix with nll right now
         } else if self.config.rustfix_coverage {