Fix some unittests for 64-bit asm. They were operating on int variables as if they were longs. This was causing asm1_1 to fail when compiled with -O3 because it was overwriting the spilled value of callee-saved register %rbx, which the runtime was using as a pointer value at the time.

module neg;

void main()
{
    int i = 32;
    long l = 55;
    float f = 23;
    double d = 4;
    assert(-i == -32);
    assert(-l == -55);
    assert(-f == -23);
    assert(-d == -4);
}