Math: Use toUpperCase() in the new generateUUID to match previous UUIDs. See #12432.

src/math/Math.js

@@ -11,9 +11,9 @@ var _Math = {
 	generateUUID: ( function () {
 
 		// http://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid-in-javascript/21963136#21963136
-		
-		var lut = []; for (var i=0; i<256; i++) { lut[i] = (i<16?'0':'')+(i).toString(16); }
-		
+
+		var lut = []; for (var i=0; i<256; i++) { lut[i] = (i<16?'0':'')+(i).toString(16).toUpperCase(); }
+
 		return function () {
 			var d0 = Math.random()*0xffffffff|0;
 			var d1 = Math.random()*0xffffffff|0;