Use strict namespace behavior for mjs files. (#7545)

packages/babel-plugin-transform-modules-commonjs/test/fixtures/interop/overview/input.js

@@ -0,0 +1,15 @@
+import "foo";
+import "foo-bar";
+import "./directory/foo-bar";
+import foo from "foo2";
+import * as foo2 from "foo3";
+import {bar} from "foo4";
+import {foo as bar2} from "foo5";
+
+var test;
+export {test};
+export var test2 = 5;
+
+bar;
+bar2;
+foo;