ninja/mac: Let mac_bundle_resources keep file permissions.

Also add a test that this is true for 'copies' too.

BUG=chromium:315383
R=mark@chromium.org

Review URL: https://codereview.chromium.org/61293004

git-svn-id: http://gyp.googlecode.com/svn/trunk@1779 78cadc50-ecff-11dd-a971-7dbc132099af