fix(compiler-sfc): fix scss source map regression

close #9970
close #9969

packages/compiler-sfc/src/style/preprocessors.ts

@@ -38,12 +38,7 @@ const scss: StylePreprocessor = (source, map, options, load = require) => {
     if (map) {
       return {
         code: result.css.toString(),
-        map: merge(
-          map,
-          result.map.toJSON
-            ? result.map.toJSON()
-            : JSON.parse(result.map.toString()),
-        ),
+        map: merge(map, JSON.parse(result.map.toString())),
         errors: [],
         dependencies,
       }