Fix class inheritance in IE <=10 (T3041) (#3527)

* Fix class inheritance in IE9 & IE10 (T3041)

Internet Explorer 9&10 do not support __proto__ at all, don't have
Object.setPrototypeOf(), but have Object.getPrototypeOf().

Because of this setting the prototype is not possible, which makes the
babelHelpers.inherits() function to set __proto__ although not supported.

Afterwards Object.getPrototypeOf() is used, but this one is not
respecting the "custom" property __proto__ that we set.

The solution is to check for __proto__ first and afterwards fallback to
Object.getPrototypeOf().

* Do the same logic in babel-helper-replace-supers

* Fix tests

* Extract creation of prototype nodes to small helper

packages/babel-plugin-transform-es2015-classes/src/vanilla.js

@@ -345,9 +345,13 @@ export default class ClassTransformer {
       }
     } else {
       bareSuperNode = optimiseCall(
-        t.callExpression(
-          t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
-          [this.classRef]
+        t.logicalExpression(
+          "||",
+          t.memberExpression(this.classRef, t.identifier("__proto__")),
+          t.callExpression(
+            t.memberExpression(t.identifier("Object"), t.identifier("getPrototypeOf")),
+            [this.classRef]
+          )
         ),
         t.thisExpression(),
         bareSuperNode.arguments