c++: Fix -fstrong-eval-order for operator &&, || and , [PR82959]

c++: Fix -fstrong-eval-order for operator &&, || and , [PR82959]

P0145R3 added
"However, the operands are sequenced in the order prescribed for the built-in
operator" rule for overloaded operator calls when using the operator syntax.
op_is_ordered follows that, but added just the overloaded operators
added in that paper.  &&, || and comma operators had rules that
lhs is sequenced before rhs already in C++98.
The following patch adds those cases to op_is_ordered.

2021-03-03  Jakub Jelinek  <jakub@redhat.com>

	PR c++/82959
	* call.c (op_is_ordered): Handle TRUTH_ANDIF_EXPR, TRUTH_ORIF_EXPR
	and COMPOUND_EXPR.

	* g++.dg/cpp1z/eval-order10.C: New test.