ranger: Fix up wi_fold_in_parts for small precision types [PR104334]

ranger: Fix up wi_fold_in_parts for small precision types [PR104334]

The wide-int.h templates expect that when an int/long etc. operand is used
it will be sign-extended based on the types precision.
wi_fold_in_parts passes 3 such non-zero constants to wi::lt_p, wi::gt_p
and wi::eq_p - 1, 3 and 4, which means it was doing weird things if either
some of 1, 3 or 4 weren't representable in type, or if type was unsigned 3 bit
type 4 should be written as -4.
The following patch promotes the subtraction operands to widest_int and
uses that as the type for ?h_range variables and compares them as such.
We don't need the overflow handling because there is never an overflow.

2022-02-02  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/104334
	* range-op.cc (range_operator::wi_fold_in_parts): Change lh_range
	and rh_range type to widest_int and subtract in widest_int.  Remove
	ov_rh, ov_lh and sign vars, always perform comparisons as signed
	and use >, < and == operators for it.

	* g++.dg/opt/pr104334.C: New test.