event_manager: Record timestamp in IntentStart even the tracing is not
triggered due to null intent.

If the intent is null, the tracing will be delayed to the following
ActivitLaunced event. And the starting timestamp won't be recorded.
This causes the drop of the trace due to no starting timestamp.

Bug: 156000582
Test: atest iorap-functional-test
Change-Id: I2a17b72392dc9d9ff7d4d79f79dc85d38dce807d
1 file changed