LIKE escape sanity:

* Deprecate `like_escape()`
* Add a method to `$wpdb`, `->esc_like()`, and add unit tests

`$wpdb::esc_like()` is not used yet. As such, many unit tests will throw `Unexpected deprecated notice for like_escape`. Subsequent commits will alleviate this.

Props miqrogroove.
See #10041.


git-svn-id: https://develop.svn.wordpress.org/trunk@28711 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/formatting/LikeEscape.php

@@ -6,6 +6,7 @@
 class Tests_Formatting_LikeEscape extends WP_UnitTestCase {
 	/**
 	 * @ticket 10041
+	 * @expectedDeprecated like_escape
 	 */
 	function test_like_escape() {