Tests: Require `imagejpeg()` function in one more media test.

This outputs a proper message if the requirement is not met, instead of an obscure failure further in the test.

This test relies on multiple resized copies of a test JPEG image being generated and available.

Follow-up to [49010], [49024], [49025], [49045].

See #50639, #50640.

git-svn-id: https://develop.svn.wordpress.org/trunk@49050 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/media.php

@@ -2353,6 +2353,7 @@ EOF;
 	 * used in the output of `wp_get_attachment_image()`.
 	 *
 	 * @ticket 36246
+	 * @requires function imagejpeg
 	 */
 	function test_wp_get_attachment_image_should_use_wp_get_attachment_metadata() {
 		add_filter( 'wp_get_attachment_metadata', array( $this, '_filter_36246' ), 10, 2 );