Add relation between op1 & op2 to lhs_opN_relation API.

Add relation between op1 & op2 to lhs_opN_relation API.

We use the relation between op1 and op2 to help fold a statement, but
it was not provided to the lhs_op1_relation and lhs_op2_relation routines
to determine if is also creates a relation between the LHS and either operand.

	gcc/
	PR tree-optimization/104547
	* gimple-range-fold.cc (fold_using_range::range_of_range_op): Add
	the op1/op2 relation to the relation call.
	* range-op.cc (*::lhs_op1_relation): Add param.
	(*::lhs_op2_relation): Ditto.
	(operator_minus::lhs_op1_relation): New.
	(range_relational_tests): Add relation param.
	* range-op.h (lhs_op1_relation, lhs_op2_relation): Adjust prototype.

	gcc/testsuite/
	* g++.dg/pr104547.C: New.