Loop over intersected bitmaps.

compute_ranges_in_block loops over the import list and then checks the
same bit in exports.  It is nmore efficent to loop over the intersection
of the 2 bitmaps.

	PR tree-optimization/106514
	* gimple-range-path.cc (path_range_query::compute_ranges_in_block):
	Use EXECUTE_IF_AND_IN_BITMAP to loop over 2 bitmaps.