UnslashingFunctionsHelper: make sure function names are checked case-…

…insensitively

These functions should be self-contained, so should not presume that the sniff has already lowercased the function name before passing it.

This fixes a bug as, in this case, the sniff didn't actually lowercase the name before passing it to the Helper class methods, so the sniff would throw false positives for non-lowercase function calls.

Tested by adjusting some pre-existing tests for the `ValidatedSanitizedInput` sniff.

WordPress/Helpers/UnslashingFunctionsHelper.php

@@ -54,6 +54,6 @@ public static function get_unslashing_functions() {
 	 * @return bool
 	 */
 	public static function is_unslashing_function( $functionName ) {
-		return isset( self::$unslashingFunctions[ $functionName ] );
+		return isset( self::$unslashingFunctions[ strtolower( $functionName ) ] );
 	}
 }

WordPress/Tests/Security/ValidatedSanitizedInputUnitTest.1.inc

@@ -113,7 +113,7 @@ if ( is_array( $_GET['test'] ) ) {} // Ok.
 output( "some string \$_POST[some_var]" ); // Ok.
 output( "some string \\$_POST[some_var] $_GET[evil]" ); // Bad x2.
 
-echo esc_html( wp_strip_all_tags( wp_unslash( $_GET['a'] ) ) ); // Ok.
+echo esc_html( wp_strip_all_tags( WP_Unslash( $_GET['a'] ) ) ); // Ok.
 
 // Test validation check vs anonymous functions.
 isset( $_POST['abc'] ); // Validation in global scope, not function scope.