Fix class inheritance in IE10 (#7969)

* Revert "Move subclass inheritance to end (#7772)"

This reverts commit f8ab9466d3.

* Only use getPrototypeOf if setPrototypeOf is implemented

* Update fixtures

* Helpers updates

* Update fixtures

* Fall back to getPrototypeOf

* Update fixtures

packages/babel-plugin-transform-classes/test/fixtures/loose-classCallCheck/with-superClass/output.js

@@ -1,7 +1,7 @@
-function _inheritsLoose(subClass, superClass) { subClass.prototype.__proto__ = superClass && superClass.prototype; subClass.__proto__ = superClass; }
-
 function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }
 
+function _inheritsLoose(subClass, superClass) { subClass.prototype = Object.create(superClass.prototype); subClass.prototype.constructor = subClass; subClass.__proto__ = superClass; }
+
 let B = function B() {
   "use strict";
 };
@@ -11,6 +11,8 @@ let A =
 function (_B) {
   "use strict";
 
+  _inheritsLoose(A, _B);
+
   function A(track) {
     var _this;
 
@@ -18,7 +20,5 @@ function (_B) {
     return _assertThisInitialized(_this);
   }
 
-  _inheritsLoose(A, _B);
-
   return A;
 }(B);