Adjust on_entry cache to indicate if the value was set properly.

Adjust on_entry cache to indicate if the value was set properly.

	* gimple-range-cache.cc (class ssa_block_ranges): Adjust prototype.
	(sbr_vector::set_bb_range): Return true.
	(class sbr_sparse_bitmap): Adjust.
	(sbr_sparse_bitmap::set_bb_range): Return value.
	(block_range_cache::set_bb_range): Return value.
	(ranger_cache::propagate_cache): Use return value to print msg.
	* gimple-range-cache.h (class block_range_cache): Adjust.