Add device_id_ in hip::event to match cuda behaviour in
hipEventQuery() and hipEventRecord().
Enable hipEventElapsedTime test on AMD platform.
Workarround sporadic crash of hipEventIpc test due to
some bug of event ipc.
Add missing hipEventDestroy() in some event tests.
Fix some logic code errors.
Fix typo in comment.
Change-Id: I9ec74c475161b3e31df48d193449023e921f2924
Associated change is to optimize event recording so it uses
agent-scope releaes (since it was only using system-scope release
to support non-coherent host mem).
Flags and environment variables exist to obtain previous behavior
if desired. Options are documented in new performance guide.