Summary:
@public
Right now the profiler shows how long the executor took on JS but doesn't show
how long each of the batched calls took, this adds a *very* high level view of JS
execution (still doesn't show properly calls dispatched with setImmediate)
Also added a global property on JS to avoid trips to Native when profiling is
disabled.
Test Plan:
Run the Profiler on any app
{F22491690}