Bug 1572227 - Warp should wait for pause events. r=bhackett

Differential Revision: https://phabricator.services.mozilla.com/D41085

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

devtools/shared/fronts/thread.js

@@ -185,7 +185,9 @@ class ThreadFront extends FrontClassWithSpec(threadSpec) {
     if (this.paused) {
       return warp();
     }
-    return this.interrupt().then(warp);
+
+    this.interrupt();
+    return this.once("paused", warp);
   }
 
   /**