Parse string export names by default (moduleStringNames) (#13195)

* Parse string epxort names by default (`moduleStringNames`)

* Remove remaining references

packages/babel-parser/test/fixtures/flow/module-string-names/import-local-is-string/options.json

@@ -1,8 +1,5 @@
 {
   "sourceType": "module",
-  "plugins": [
-    "moduleStringNames",
-    "flow"
-  ],
+  "plugins": ["flow"],
   "throws": "A string literal cannot be used as an imported binding.\n- Did you mean `import { \"foo\" as foo }`? (1:9)"
 }

packages/babel-parser/test/fixtures/flow/module-string-names/options.json

@@ -1,4 +1,4 @@
 {
   "sourceType": "module",
-  "plugins": ["flow", "moduleStringNames"]
+  "plugins": ["flow"]
 }