Ensure built CSS files are present in tests

Author: westonruter

tests/phpunit/tests/media.php

@@ -6677,6 +6677,9 @@ static function () {
 	 * @dataProvider data_provider_data_provider_to_test_wp_enqueue_img_auto_sizes_contain_css_fix
 	 */
 	public function test_wp_enqueue_img_auto_sizes_contain_css_fix( ?Closure $set_up, bool $expected, ?string $expected_deprecated = null ): void {
+		// This file is created as part of the build process, but the unit tests don't run the build prior to running unit tests on GHA.
+		self::touch( ABSPATH . WPINC . '/css/dist/block-library/common.css' );
+
 		if ( $set_up ) {
 			$set_up();
 		}

tests/phpunit/tests/template.php

@@ -1677,6 +1677,9 @@ function (): void {
 	 * @dataProvider data_wp_hoist_late_printed_styles
 	 */
 	public function test_wp_hoist_late_printed_styles( ?Closure $set_up, int $inline_size_limit, array $expected_styles ): void {
+		// This file is created as part of the build process, but the unit tests don't run the build prior to running unit tests on GHA.
+		self::touch( ABSPATH . WPINC . '/css/dist/block-library/theme.css' );
+
 		switch_theme( 'default' );
 		global $wp_styles;
 		$wp_styles = null;