Themes: Get the correct theme when template and stylesheet were both passed as arguments.

Fixes a bug where `$new_theme` got set before the second argument was
appropriately handled, causing the `current_theme` option to later always be
updated to the parent theme's name.

Introduced in [21131].

Props obenland, wonderboymusic.
Fixes #32635.



git-svn-id: https://develop.svn.wordpress.org/trunk@33815 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/theme.php

@@ -85,6 +85,11 @@ class Tests_Theme extends WP_UnitTestCase {
 		$themes = get_themes();
 		// Generic tests that should hold true for any theme
 		foreach ( $themes as $k => $theme ) {
+			// Don't run these checks for custom themes.
+			if ( empty( $theme['Author'] ) || false === strpos( $theme['Author'], 'WordPress' ) ) {
+				continue;
+			}
+
 			$this->assertEquals( $theme['Name'], $k );
 			$this->assertNotEmpty( $theme['Title'] );