Jira Plugin override system javascript file

[Matthias Günter]

I'm about to release a plugin, but currently have problems with a PolyFill in Internet Explorer. My frontend of the plugin works with a JavaScript Model driven state management [MobX](https://github.com/mobxjs/mobx). It depends on an ES6 function [`Array.prototype.find`](https://github.com/paulmillr/Array.prototype.find). This polyfill is described as follow in Jira core:

module-key = 'jira.webresources:find-polyfill'
location = '/static/lib/polyfills/find/find-polyfill.js'

When I have a look at the content of that file the polyfill is incorrect:

if (!Array.prototype.find) {
    Object.defineProperty(Array.prototype, 'find', {        value: function(predicate) {
            // 1. Let O be ? ToObject(this value).
            if (this == null) {
                throw new TypeError('"this" is null or not defined');
            }

            var o = Object(this);

            // 2. Let len be ? ToLength(? Get(O, "length")).
            var len = o.length >>> 0;

            // 3. If IsCallable(predicate) is false, throw a TypeError exception.
            if (typeof predicate !== 'function') {
                throw new TypeError('predicate must be a function');
            }

            // 4. If thisArg was supplied, let T be thisArg; else let T be undefined.
            var thisArg = arguments[1];

            // 5. Let k be 0.
            var k = 0;

            // 6. Repeat, while k < len
            while (k < len) {
                // a. Let Pk be ! ToString(k).
                // b. Let kValue be ? Get(O, Pk).
                // c. Let testResult be ToBoolean(? Call(predicate, T, kValue, k, O )).
                // d. If testResult is true, return kValue.
                var kValue = o[k];
                if (predicate.call(thisArg, kValue, k, o)) {
                    return kValue;
                }
                // e. Increase k by 1.                k++;
            }

            // 7. Return undefined.
            return undefined;
        }
    });
}

According to the community, I quote the erroneous behavior:

[...] by the spec, `Array.prototype.find` descriptor should be `{writable: true, enumerable: false, configurable: true}` and `core-js` use it. [...] - zloirock

Is there any possibility to:

- Change the system file /static/lib/polyfills/find/find-polyfill.js?
- Load a web resource before the jira.webresources:find-polyfill resource so I can hook with the correct polyfill?
- Override the web resource via atlassian-plugin.xml?

The correct implementation of the polyfill is described here: https://github.com/mobxjs/mobx/issues/1028#issuecomment-378940977

This is a duplicate post of https://stackoverflow.com/questions/54721948/jira-plugin-override-system-file