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 switch2;
extern(C) int printf(char*, ...);

void main()
{
    int i = 2;
    switch(i)
    {
    case 0: assert(0);
    case 1,2: printf("hello world\n"); break;
    default: assert(0);
    }
}