Remove whitespace generation (#5833)

* Remove whitespace generation and rely on default printing

Changes to printing:
* Add newline after last empty SwitchCase
* Add newlines around block comments if they are non-flow comments or contain newlines

* Fix a few more fixtures

packages/babel-plugin-transform-es2015-classes/test/fixtures/loose/super-function-fallback/expected.js

@@ -1,3 +1,3 @@
 var Test = function Test() {
   Function.prototype.hasOwnProperty.call(this, "test");
-};
+};