Move Promise Tracker out of hidden experiments.

Source/devtools/front_end/main/Main.js

Index: Source/devtools/front_end/main/Main.js
diff --git a/Source/devtools/front_end/main/Main.js b/Source/devtools/front_end/main/Main.js
index 21690e763b736fe3b156f73db673c7a10c33248d..13556ec891984c54b738138ffb231b148243d28d 100644
--- a/Source/devtools/front_end/main/Main.js
+++ b/Source/devtools/front_end/main/Main.js
@@ -155,7 +155,7 @@ WebInspector.Main.prototype = {
         Runtime.experiments.register("fileSystemInspection", "FileSystem inspection");
         Runtime.experiments.register("gpuTimeline", "GPU data on timeline", true);
         Runtime.experiments.register("layersPanel", "Layers panel");
-        Runtime.experiments.register("promiseTracker", "Enable Promise inspection", true);
+        Runtime.experiments.register("promiseTracker", "Enable Promise inspection");
         Runtime.experiments.register("timelineOnTraceEvents", "Timeline on trace events");
         Runtime.experiments.register("timelinePowerProfiler", "Timeline power profiler");
         Runtime.experiments.register("timelineJSCPUProfile", "Timeline with JS sampling");