Move simplify_cond_using_ranges_2 to tree-vrp.c

Move simplify_cond_using_ranges_2 to tree-vrp.c

This was slated to be moved last year, as its only use is in tree-vrp.c

There are no functional changes.  It's just a move and a rename.

gcc/ChangeLog:

	* vr-values.h: Remove simplify_cond_using_ranges_2.
	(range_fits_type_p): New.
	* vr-values.c (range_fits_type_p): Remove static qualifier.
	(vrp_simplify_cond_using_ranges): Move...
	* tree-vrp.c (vrp_simplify_cond_using_ranges): ...to here.