[XSS] Fix harmless dots in URLs not being replaced

[pettinen]

InjectionChecker._removeDots was called with this bound to globalThis instead of InjectionChecker, causing the dot-replace intended to reduce false positives to not work properly:

_removeDots(p) {
  // this === [object DedicatedWorkerGlobalScope]
  // this._dotRx === undefined
  return p.replace(this._dotRx, '|');
},
...
expr.replace(this._removeDotsRx, this._removeDots)

Fixes #415 at least.

---

I considered doing simply

-expr.replace(this._removeDotsRx, this._removeDots)
+expr.replace(this._removeDotsRx, (p) => p.replace(this._dotRx, '|'))

but presumably there might be some performance benefit from defining a function only once.