Themes: Fix core block style paths on Windows.

This is a follow-up to [56528], which normalizes the `BLOCKS_PATH` for Windows prior to making paths relative for caches during the registration process. Prior to this change, incorrect file paths would lead to broken styles for core blocks on Windows.

Props wildworks, pbiron, flixos90, joemcgill.
Fixes #59489. See #59111.


git-svn-id: https://develop.svn.wordpress.org/trunk@56785 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/blocks/index.php

@@ -68,9 +68,13 @@ function register_core_block_style_handles() {
 
 	if ( ! $files ) {
 		$files = glob( wp_normalize_path( BLOCKS_PATH . '**/**.css' ) );
+
+		// Normalize BLOCKS_PATH prior to substitution for Windows environments.
+		$normalized_blocks_path = wp_normalize_path( BLOCKS_PATH );
+
 		$files = array_map(
-			static function ( $file ) {
-				return str_replace( BLOCKS_PATH, '', $file );
+			static function ( $file ) use ( $normalized_blocks_path ) {
+				return str_replace( $normalized_blocks_path, '', $file );
 			},
 			$files
 		);