Dump profile-based number of iterations

Dump profile-based number of iterations

	* analyze_brprob.py: Parse and display average number
	of loop iterations.
	* cfgloop.c (flow_loop_dump): Dump average number of loop iterations.
	* cfgloop.h: Change 'struct loop' to 'const struct loop' for a
	few functions.
	* cfgloopanal.c (expected_loop_iterations_unbounded): Set a new
	argument to true if the expected number of iterations is
	loop-based.

From-SVN: r237762