dillon1000/react

Profiler actualDuration bugfix (#13313)

* Simplified profiler actualDuration timing

While testing the new DevTools profiler, I noticed that sometimes– in larger, more complicated applications– the actualDuration value was incorrect (either too large, or sometimes negative). I was not able to reproduce this in a smaller application or test (which sucks) but I assume it has something to do with the way I was tracking render times across priorities/roots. So this PR replaces the previous approach with a simpler one.

* Changed bubbling logic after chatting out of band with Andrew

* Replaced __PROFILE__ with feature-flag conditionals in test

* Updated test comment