inferno: sort threads by the event count in a thread.

Sometimes a thread having only several samples comes first, and looks
like it is the most important thread. So sort threads by the event
count to make really important threads shows first.

Bug: none.
Test: run inferno.sh.
Change-Id: Ic8406fb19d72d2599c78589d9f4876875dad00e8
1 file changed