Request for reviews (M): 7004555: Add new policy for one iteration loops

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/7004555/webrev

Fixed 7004555: Add new policy for one iteration loops

Add new policy for one iteration loops (mostly formal pre- loops) to fold exit 
condition and avoid going through do_maximally_unroll() as we do currently for 
such cases.
Move exact trip count calculation from policy_maximally_unroll() into separate 
method. Note, trip_count type is changed to unsigned int and its range is 
changed to [0, max_juint). Add new flag HasExactTripCount to indicate that 
loop's limits and trip count are constants.
Check for non overlaping init and limit values to avoid zero trip guard 
generation in remove_empty_loop.
Rename some CountedLoopNode flags.
Print loop iv range for counted loops dumps:

Loop: N286/N193  predicated counted [0,2),+1