Recurse exception handling to better handle '{{}}' in place of recently installed fix (#9548)

* Introduced preliminary idea for infinite recurse exception

* Better handling of infinite recursion

But it could be better still...

* the TransclusionError is a proper error

Moved the magic number to be on the error's class. Not sure if that's
a great idea.

* Fixed minor minor issue that came up in conflict

The minor fix to the jasmine regexp that escaped a '+' somehow
broke some random test.

* Removing patch fix for recursion errors

* Fixed issue where buttton and other widgets don't clean up

* Added release notes for #9548

* Update test-widget.js

If I don't fix those indentations, the entire TW codebase will explode or soemthing.

* Update test-widget.js

These lint problems are wasting my time.

* Fixed all core widgets to not leak when renderChildren fails

* Updated release notes to reflect what I'm actually fixing

* Update test-widget.js

Added warning not to use for-of loop for defining tests. The iterating variable needs to have its own method scope, or it risks being the same value for all tests.

core/modules/widgets/diff-text.js

@@ -59,6 +59,8 @@ DiffTextWidget.prototype.render = function(parent,nextSibling) {
 	var domContainer = this.document.createElement("div"), 
 		domDiff = this.createDiffDom(diffs);
 	parent.insertBefore(domContainer,nextSibling);
+	// Save our container
+	this.domNodes.push(domContainer);
 	// Set variables
 	this.setVariable("diff-count",diffs.reduce(function(acc,diff) {
 		if(diff[0] !== dmp.DIFF_EQUAL) {
@@ -70,8 +72,6 @@ DiffTextWidget.prototype.render = function(parent,nextSibling) {
 	this.renderChildren(domContainer,null);
 	// Render the diff
 	domContainer.appendChild(domDiff);
-	// Save our container
-	this.domNodes.push(domContainer);
 };
 
 /*