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-object-rest-spread/test/fixtures/object-rest/nested/expected.js

@@ -6,6 +6,11 @@ const defunct = {
     }
   }
 };
-
-const { outer: { inner: { three } } } = defunct,
-      other = babelHelpers.objectWithoutProperties(defunct.outer.inner, ["three"]);
+const {
+  outer: {
+    inner: {
+      three
+    }
+  }
+} = defunct,
+      other = babelHelpers.objectWithoutProperties(defunct.outer.inner, ["three"]);