Speed up reveal widget

It turns out that the `localeCompare` function used by `compareStateText()` is very, very slow. Replacing it with a straightforward equality test makes one of my test rigs be 10x faster...

Note that this PR reverts the behaviour of match/nomatch to that before #3157. That change was not backwards compatible in that the switch to localeCompare meant that é === e, now it doesn't again.

core/modules/widgets/reveal.js

@@ -142,10 +142,10 @@ RevealWidget.prototype.readState = function() {
 			this.readPopupState(state);
 			break;
 		case "match":
-			this.isOpen = !!(this.compareStateText(state) == 0);
+			this.isOpen = this.text === state;
 			break;
 		case "nomatch":
-			this.isOpen = !(this.compareStateText(state) == 0);
+			this.isOpen = this.text !== state;
 			break;
 		case "lt":
 			this.isOpen = !!(this.compareStateText(state) < 0);