Themes: Normalize the installed theme path in Theme_Installer_Skin::do_overwrite() before comparing with the uploaded theme.

This ensures that the data for the currently installed theme is picked up properly when uploading a theme update on Windows.

Follow-up to [48390].

Props bobbingwide, wpamitkumar, mukesh27.
Fixes #51182.
Built from https://develop.svn.wordpress.org/trunk@48913


git-svn-id: http://core.svn.wordpress.org/trunk@48675 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-theme-installer-skin.php

@@ -206,7 +206,9 @@ class Theme_Installer_Skin extends WP_Upgrader_Skin {
 		$all_themes         = wp_get_themes( array( 'errors' => null ) );
 
 		foreach ( $all_themes as $theme ) {
-			if ( rtrim( $theme->get_stylesheet_directory(), '/' ) !== $folder ) {
+			$stylesheet_dir = wp_normalize_path( $theme->get_stylesheet_directory() );
+
+			if ( rtrim( $stylesheet_dir, '/' ) !== $folder ) {
 				continue;
 			}