Remove test from 32bit Windows

Windows is only sending low-memory notifications when the machine
is reaching low-memory. So running a 32bit process on 64bit machine
can easily exhaust address space before machine gets close to
low-memory.

src/test/perf/low_memory/low-memory.cc

@@ -112,6 +112,9 @@ int main(int, char**)
     return 0;
   }
 
+#if defined(WIN32) && !defined(SNMALLOC_VA_BITS_64)
+  std::cout << "32-bit windows not supported for this test." << std::endl;
+#else
   setup();
 
   for(size_t i = 0; i < 10; i++)
@@ -122,6 +125,6 @@ int main(int, char**)
     reduce_pressure(allocations);
 
   }
-
+#endif
   return 0;
 }