Bug 1597227 - Remove forced GC when closing a httpd.js connection. r=froydnj

The forced garbage collection has been added a decade ago for a test that
exhibited a memory increase over time in Firefox. Now that the test is no
longer present in the tree, and the garbage collector got a lot of improvements
over the last years, there is no compelling reason to keep the call to
"forceGC()" in the closing handler of httpd.js.

Differential Revision: https://phabricator.services.mozilla.com/D58550

--HG--
extra : moz-landing-system : lando

netwerk/test/httpserver/httpd.js

@@ -861,10 +861,6 @@ nsHttpServer.prototype = {
     if (!this._hasOpenConnections() && this._socketClosed) {
       this._notifyStopped();
     }
-    // Bug 508125: Add a GC here else we'll use gigabytes of memory running
-    // mochitests. We can't rely on xpcshell doing an automated GC, as that
-    // would interfere with testing GC stuff...
-    Cu.forceGC();
   },
 
   /**