Bug 1600565 - Fix changes to CCRunnerFired made during previous refactoring r=mccr8

One thing I inadvertantly changed was that didDoWork gets set to true even if we don't call FireForgetSkippable and execute what was the third branch of the if statement:

https://searchfox.org/mozilla-central/rev/883d58bccf1a36465ef5ee14b62db0a9925ab85b/dom/base/nsJSEnvironment.cpp#1878-1883

Differential Revision: https://phabricator.services.mozilla.com/D56021

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

dom/base/nsJSEnvironment.cpp

@@ -1884,10 +1884,12 @@ static bool CCRunnerFired(TimeStamp aDeadline) {
       MOZ_FALLTHROUGH;
 
     case CCRunnerState::LateTimer:
-      if (!ShouldTriggerCC(suspected) && ShouldFireForgetSkippable(suspected)) {
-        FireForgetSkippable(suspected, /* aRemoveChildless = */ false,
-                            aDeadline);
-        didDoWork = true;
+      if (!ShouldTriggerCC(suspected)) {
+        if (ShouldFireForgetSkippable(suspected)) {
+          FireForgetSkippable(suspected, /* aRemoveChildless = */ false,
+                              aDeadline);
+          didDoWork = true;
+        }
         finished = true;
         break;
       }
@@ -1916,10 +1918,12 @@ static bool CCRunnerFired(TimeStamp aDeadline) {
       break;
 
     case CCRunnerState::FinalTimer:
-      if (!ShouldTriggerCC(suspected) && ShouldFireForgetSkippable(suspected)) {
-        FireForgetSkippable(suspected, /* aRemoveChildless = */ false,
-                            aDeadline);
-        didDoWork = true;
+      if (!ShouldTriggerCC(suspected)) {
+        if (ShouldFireForgetSkippable(suspected)) {
+          FireForgetSkippable(suspected, /* aRemoveChildless = */ false,
+                              aDeadline);
+          didDoWork = true;
+        }
         finished = true;
         break;
       }