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 strings2;

import std.string;
import std.stdio;

void main()
{
    int i = 32;
    auto str = format(i);
    writefln(str);

    long l = 123123;
    str = format(l);
    writefln(str);
}