drupal_get_css removes non-rtl files when using drupal_add_css with basename

locale_css_alter removes non-rtl files when using drupal_add_css with basename
Steps to reproduce:
1 - use drupal_add_css to add a file and add 'basename' argument
drupal_add_css('path/tofile/test', array(
'group' => CSS_DEFAULT,
'basename' => 'test-css',
));
2 - Create 2 files test.css and test-rtl.css
3 - Open an RTL page that should have the file.

Expected behavior:
test.css and test-rtl.css should be included.

Actual behavior:
only test-rtl.css is included on that page

Additional info:
drupal_get_css will remove the non-rtl file
if (isset($previous_item[$basename])) {
// Remove the previous item that shared the same base name.
unset($css[$previous_item[$basename]]);
}

Fix:
Changing basename alongside rtl path in locale_css_alter