Move constructors should not be POD

[WalterBright]

struct A
{
            int arr;
            this(A rhs) // move constructor not called
            {
                printf("this(A)\n");
                arr = rhs.arr;
                rhs.arr = 0;
            }
}

void main()
{
    A a;
    a.arr = 1;

    A b = __rvalue(a); // move constructor should get called
    b.arr += 1;
    assert(a.arr == 0);
    assert(b.arr == 2);
}

Adding in a copy constructor or destructor causes it to pass, because then it is non-POD and the move constructor gets passed.

See also #20616