message: memory testcase: add barriers on MSVC
diff: */
  #include "test.h"
  +#if defined(_MSC_VER)
  +# include <windows.h>
  +#endif
  ENOKI_TEST_ALL(test01_load) {
  alignas(alignof(T)) Value mem[Size];
  @@ -56,7 +59,7 @@ ENOKI_TEST_ALL(test05_gather) {
  #if defined(_MSC_VER)
  /// MSVC doesn't seem to correctly track data dependencies involving gathers
  - std::cout << mem[0] << std::endl;
  + MemoryBarrier();
  #endif
  store(dst, gather<T>(mem, id32));
  @@ -64,10 +67,9 @@ ENOKI_TEST_ALL(test05_gather) {
  assert(dst[i] == Value(Size - 1 - i));
  memset(dst, 0, sizeof(Value) * Size);
  -
  #if defined(_MSC_VER)
  /// MSVC doesn't seem to correctly track data dependencies involving gathers
  - std::cout << mem[0] << std::endl;
  + MemoryBarrier();
  #endif
  store(dst, gather<T>(mem, id64));
  @@ -127,7 +129,7 @@ ENOKI_TEST_ALL(test07_gather_mask) {
  #if defined(_MSC_VER)
  /// MSVC doesn't seem to correctly track data dependencies involving gathers
  - std::cout << mem[0] << std::endl;
  + MemoryBarrier();
  #endif
  memset(dst, 0, sizeof(Value) * Size);
  @@ -138,7 +140,7 @@ ENOKI_TEST_ALL(test07_gather_mask) {
  #if defined(_MSC_VER)
  /// MSVC doesn't seem to correctly track data dependencies involving gathers
  - std::cout << mem[0] << std::endl;
  + MemoryBarrier();
  #endif
  store(dst, gather<T>(mem, id64, even_mask));
  