Bug 1685830 - Remove spurious check that prevents preload from working in non-http(s) sites. r=smaug

As it doesn't match other implementations, and it's confusing.

Differential Revision: https://phabricator.services.mozilla.com/D101248

dom/html/HTMLLinkElement.cpp

@@ -736,10 +736,8 @@ void HTMLLinkElement::CancelPrefetchOrPreload() {
 
 void HTMLLinkElement::StartPreload(nsContentPolicyType aPolicyType) {
   MOZ_ASSERT(!mPreload, "Forgot to cancel the running preload");
-
-  auto referrerInfo = MakeRefPtr<ReferrerInfo>(*this);
-  RefPtr<PreloaderBase> preload = OwnerDoc()->Preloads().PreloadLinkElement(
-      this, aPolicyType, referrerInfo);
+  RefPtr<PreloaderBase> preload =
+      OwnerDoc()->Preloads().PreloadLinkElement(this, aPolicyType);
   mPreload = preload.get();
 }