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/src/transformClass.js

@@ -179,7 +179,6 @@ export default function transformClass(
     }
 
     pushDescriptors();
-    pushInheritsToBody();
   }
 
   function pushBody() {
@@ -263,6 +262,8 @@ export default function transformClass(
   }
 
   function pushDescriptors() {
+    pushInheritsToBody();
+
     const { body } = classState;
 
     let instanceProps;
@@ -572,6 +573,8 @@ export default function transformClass(
     }
 
     classState.body.push(classState.construct);
+
+    pushInheritsToBody();
   }
 
   /**
@@ -582,9 +585,9 @@ export default function transformClass(
 
     setState({ pushedInherits: true });
 
-    // Push to ensure that the constructor inheritance is set up after
+    // Unshift to ensure that the constructor inheritance is set up before
     // any properties can be assigned to the prototype.
-    classState.body.push(
+    classState.body.unshift(
       t.expressionStatement(
         t.callExpression(
           classState.file.addHelper(