Fix ReferenceError in the wrapNativeSuper helper (#8100)

Fix a ReferenceError caused by a typo (`_construct` instead of
`construct`) in the external `wrapNativeSuper` helper. (The typo
doesn't usually cause an error in inline helpers because `_construct`
happens to be the default name given to the `construct` helper
function.)

packages/babel-plugin-transform-classes/test/fixtures/extend-builtins/super-called/exec.js

@@ -6,7 +6,7 @@ var env = {
   }
 };
 
-// Wee need to use "with" to avoid leaking the modified Array to other tests.
+// We need to use "with" to avoid leaking the modified Array to other tests.
 with (env) {
   class List extends Array {};
   new List();