Move common code from range-op.cc to header files.

In preparation for the agnostication of ranger, this patch moves
common code that can be shared between non-integer ranges (initially
pointers) into the relevant header files.

This is a relatively non-invasive change, as any changes that would
need to be ported to GCC 12, would occur in the range-op entries
themselves, not in the supporting glue which I'm moving.

Tested and benchmarked on x86-64 Linux.

gcc/ChangeLog:

	* range-op.cc (empty_range_varying): Move to range-op.h.
	(range_true): Move to range.h.
	(range_false): Same.
	(range_true_and_false): Same.
	(enum bool_range_state): Move to range-op.h.
	(relop_early_resolve): Same.
	(operator_equal::op1_op2_relation): Abstract code to...
	(equal_op1_op2_relation): ...here.
	(operator_not_equal::op1_op2_relation): Abstract code to...
	(not_equal_op1_op2_relation): ...here.
	(operator_lt::op1_op2_relation): Abstract code to...
	(lt_op1_op2_relation): ...here.
	(operator_le::op1_op2_relation): Abstract code to...
	(le_op1_op2_relation): ...here.
	(operator_gt::op1_op2_relation): Abstract code to...
	(gt_op1_op2_relation): ...here.
	(operator_ge::op1_op2_relation): Abstract code to...
	(ge_op1_op2_relation): ...here.
	(class range_op_table): Move to range-op.h.
	* range-op.h (equal_op1_op2_relation): Moved from range-op.cc.
	(not_equal_op1_op2_relation): Same.
	(lt_op1_op2_relation): Same.
	(le_op1_op2_relation): Same.
	(gt_op1_op2_relation): Same.
	(ge_op1_op2_relation): Same.
	(enum bool_range_state): Same.
	(get_bool_state): Same.
	(empty_range_varying): Same.
	(relop_early_resolve): Same.
	(class range_op_table): Same.
	* range.h (range_true): Same.
	(range_false): Same.
	(range_true_and_false): Same.