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-function-bind/test/fixtures/function-bind/bind/expected.js

@@ -1,5 +1,7 @@
 var _context;
 
 var f = (_context = ctx, ns.obj.func).bind(_context);
+
 var g = (_context = ns.obj).func.bind(_context);
-var h = (_context = new X(), y).bind(_context);
+
+var h = (_context = new X(), y).bind(_context);