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 bug2;
struct Vec { Vec barf() { return Vec(); } }
class test { this(Vec whee) { } }
void main() { Vec whee; new test(whee.barf()); }