Bug 1815524 - Round up FirstStartup timing probes to the nearest uint. r=rhelmer

This is because sometimes these timings will be less than 1 millisecond, and we
were coercing those fractional numbers to a uint which caused it to become 0.

This patch causes us to round up to the nearest uint instead.

It also adds the AppConstants.MOZ_NORMANDY condition for recording the timing
value for Normandy init, which I'd somehow missed the first time.

Differential Revision: https://phabricator.services.mozilla.com/D182785

toolkit/modules/FirstStartup.sys.mjs

@@ -86,13 +86,15 @@ export var FirstStartup = {
       this._state = this.UNSUPPORTED;
     }
 
-    Glean.firstStartup.normandyInitTime.set(
-      normandyInitEndTime || Cu.now() - startingTime
-    );
+    if (AppConstants.MOZ_NORMANDY) {
+      Glean.firstStartup.normandyInitTime.set(
+        Math.ceil(normandyInitEndTime || Cu.now() - startingTime)
+      );
+    }
 
     if (AppConstants.MOZ_UPDATE_AGENT) {
       Glean.firstStartup.deleteTasksTime.set(
-        deleteTasksEndTime || Cu.now() - startingTime
+        Math.ceil(deleteTasksEndTime || Cu.now() - startingTime)
       );
     }