Themes: Remove memoization from stylesheet and theme directories.

This fixes bugs introduced in [56635] whereby the template or stylesheet path could be memoized incorrectly if `get_template_directory()` or `get_stylesheet_directory()` were called before the theme has been fully initialized.

Props partyfrikadelle, coreyw, kdowns, rebasaurus, meta4, flixos90, mukesh27, joemcgill.
Fixes #59847.


git-svn-id: https://develop.svn.wordpress.org/trunk@57129 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/data/themedir2/test-parent/functions.php

@@ -0,0 +1,7 @@
+<?php
+
+// Dummy theme.
+
+echo __DIR__ . '/' . basename(__FILE__);
+
+?>

tests/phpunit/data/themedir2/test-parent/index.php

@@ -0,0 +1,7 @@
+<?php
+
+// Dummy theme.
+
+echo __DIR__ . '/' . basename(__FILE__);
+
+?>

tests/phpunit/data/themedir2/test-parent/style.css

@@ -0,0 +1,12 @@
+/*
+Theme Name: Test Parent Theme
+Theme URI: http://example.org/
+Description: An example parent theme
+Version: 1.3
+Author: Minnie Bannister
+Author URI: http://example.com/
+Template: test-parent
+*/
+
+
+

tests/phpunit/data/themedir2/test/functions.php

@@ -0,0 +1,7 @@
+<?php
+
+// Dummy theme.
+
+echo __DIR__ . '/' . basename(__FILE__);
+
+?>

tests/phpunit/data/themedir2/test/index.php

@@ -0,0 +1,7 @@
+<?php
+
+// Dummy theme.
+
+echo __DIR__ . '/' . basename(__FILE__);
+
+?>

tests/phpunit/data/themedir2/test/style.css

@@ -0,0 +1,12 @@
+/*
+Theme Name: Test Theme
+Theme URI: http://example.org/
+Description: An example theme
+Version: 1.3
+Author: Minnie Bannister
+Author URI: http://example.com/
+Template: test-parent
+*/
+
+
+