Subzero. Removes X8664_STACK_HACK from the crosstests.

crosstest/simple_loop_main.c

 /* crosstest.py --test=simple_loop.c --driver=simple_loop_main.c \
    --prefix=Subzero_ --output=simple_loop */
 
 #include <stdio.h>
 
 int simple_loop(int *a, int n);
 int Subzero_simple_loop(int *a, int n);
 
-#ifdef X8664_STACK_HACK
-int wrapped_main(int argc, char *argv[]) {
-#else  // !defined(X8664_STACK_HACK)
 int main(int argc, char *argv[]) {
-#endif // X8664_STACK_HACK
   unsigned TotalTests = 0;
   unsigned Passes = 0;
   unsigned Failures = 0;
   int a[100];
   for (int i = 0; i < 100; ++i)
     a[i] = i * 2 - 100;
   for (int i = -2; i < 100; ++i) {
     ++TotalTests;
     int llc_result = simple_loop(a, i);
     int sz_result = Subzero_simple_loop(a, i);
     if (llc_result == sz_result) {
       ++Passes;
     } else {
       ++Failures;
       printf("Failure: i=%d, llc=%d, sz=%d\n", i, llc_result, sz_result);
     }
   }
   printf("TotalTests=%u Passes=%u Failures=%u\n", TotalTests, Passes, Failures);
   return Failures;
 }