Capture and remove matcher binding breaks IE 11

I'm submitting a bug report

Library Version: 1.12.0

Please tell us about your environment:

Operating System: Windows 10
Node Version: 12.3.1
NPM Version: 6.9.0
JSPM OR Webpack AND Version Aurelia CLI 1.2.2 with requireJS
Browser: IE 11
Language: ESNext

Current behavior: Commit a5796443016d2c87269dd05801c057fb45e5dc44 introduced a breaking change for IE 11 lines https://github.com/aurelia/templating-resources/blob/d346a817157960d54098a9193fc58c264ceedca6/src/repeat.ts#L289 and https://github.com/aurelia/templating-resources/blob/d346a817157960d54098a9193fc58c264ceedca6/src/repeat.ts#L295 require polyfills for documentFragment.children and documentFragment.firstElementChild respectively.

Without them in my case this caused console errors and the app failed to load. Expected/desired behavior:

What is the expected behavior? App runs in IE 11
What is the motivation / use case for changing the behavior? Maintain IE 11 compatibility

Additional Info For my app I added the polyfills from MDN: https://developer.mozilla.org/en-US/docs/Web/API/ParentNode/children

// Overwrites native 'children' prototype.
// Adds Document & DocumentFragment support for IE9 & Safari.
// Returns array instead of HTMLCollection.
;(function(constructor) {
if (constructor &&
constructor.prototype &&
constructor.prototype.children == null) {
Object.defineProperty(constructor.prototype, 'children', {
  get: function() {
    var i = 0, node, nodes = this.childNodes, children = [];
    while (node = nodes[i++]) {
      if (node.nodeType === 1) {
        children.push(node);
      }
    }
    return children;
  }
});
}
})(window.Node || window.Element);

https://developer.mozilla.org/en-US/docs/Web/API/ParentNode/firstElementChild

// Overwrites native 'firstElementChild' prototype.
// Adds Document & DocumentFragment support for IE9 & Safari.
;(function(constructor) {
if (constructor &&
    constructor.prototype &&
    constructor.prototype.firstElementChild == null) {
    Object.defineProperty(constructor.prototype, 'firstElementChild', {
        get: function() {
            var node, nodes = this.childNodes, i = 0;
            while (node = nodes[i++]) {
                if (node.nodeType === 1) {
                    return node;
                }
            }
            return null;
        }
    });
}
})(window.Node || window.Element);

aurelia / templating-resources

Capture and remove matcher binding breaks IE 11 #390