Bug 1578624 - P9: Adjust devtools tests to no longer expect a JS stack for parent initiated loads. r=Honza

Differential Revision: https://phabricator.services.mozilla.com/D44765

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

devtools/client/netmonitor/test/browser_net_cause.js

@@ -16,8 +16,7 @@ const EXPECTED_REQUESTS = [
     url: CAUSE_URL,
     causeType: "document",
     causeUri: null,
-    // The document load has internal privileged JS code on the stack
-    stack: true,
+    stack: false,
   },
   {
     method: "GET",

devtools/client/netmonitor/test/browser_net_websocket_stacks.js

@@ -16,7 +16,7 @@ const EXPECTED_REQUESTS = [
     url: TOP_URL,
     causeType: "document",
     causeUri: null,
-    stack: true,
+    stack: false,
   },
   {
     method: "GET",

devtools/client/netmonitor/test/browser_net_worker_stacks.js

@@ -17,7 +17,7 @@ const EXPECTED_REQUESTS = [
     url: TOP_URL,
     causeType: "document",
     causeUri: null,
-    stack: true,
+    stack: false,
   },
   {
     method: "GET",