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 bug45;

void foo() {
    int bar;
    scope(exit) { bar++; }
    if (bar) return;
}

void main() {
    foo();
}