[react-packager] Make it safe to include files without a newline at the end

Summary:
@public
Fixes #1431
Fixes #1005
Files with no newlines and a comment at the end of the file would've caused a syntax error in the bundle:

```js
__d('module', function() {
hi();
// wow })
```

This fixes the issue by inserting a new lines before `})`.

Test Plan:
* ./runJestTests.sh
* ./runJestTests.sh PackagerIntegration
* open app to the playground app
* add an error
* observe that the redbox has the correct lines

react-packager/src/DependencyResolver/haste/__tests__/HasteDependencyResolver-test.js

@@ -600,7 +600,8 @@ describe('HasteDependencyResolver', function() {
         'require("Y")',
         'require( \'z\' )',
         'require( "a")',
-        'require("b" )});',
+        'require("b" )',
+        '});',
       ].join('\n'));
     });
   });

react-packager/src/DependencyResolver/haste/index.js

@@ -20,8 +20,7 @@ var DEFINE_MODULE_CODE = [
   '_deps_,',
   'function(global, require, requireDynamic, requireLazy, module, exports) {',
   '  _code_',
-  '}',
-  ');',
+  '\n});',
 ].join('');
 
 var DEFINE_MODULE_REPLACE_RE = /_moduleName_|_code_|_deps_/g;