Customize: Remove unnecessary call to `refresh()` a CodeMirror instance upon `focus` in Code Editor control.

This also fixes an issue with the cursor not being set in the expected location with an `inputStyle=contenteditable`.

Props afercia.
See #41897.
Fixes #41900.

Built from https://develop.svn.wordpress.org/trunk@41582


git-svn-id: http://core.svn.wordpress.org/trunk@41415 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/customize-controls.js

@@ -3781,11 +3781,6 @@
 
 			control.editor = wp.codeEditor.initialize( $textarea, settings );
 
-			// Refresh when receiving focus.
-			control.editor.codemirror.on( 'focus', function( codemirror ) {
-				codemirror.refresh();
-			});
-
 			/*
 			 * When the CodeMirror instance changes, mirror to the textarea,
 			 * where we have our "true" change event handler bound.

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-41581';
+$wp_version = '4.9-alpha-41582';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.