OS::MemMove/OS::MemCopy: Don't call through to generated code when size == 0 to avoid prefetching i…

src/platform-win32.cc

Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index 272678fe649294017e9758000823da0706ab376c..94b78e45bed144d0a17b1aa904d48acf95e35f77 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -160,6 +160,7 @@ OS::MemMoveFunction CreateMemMoveFunction();
 
 // Copy memory area to disjoint memory area.
 void OS::MemMove(void* dest, const void* src, size_t size) {
+  if (size == 0) return;
   // Note: here we rely on dependent reads being ordered. This is true
   // on all architectures we currently support.
   (*memmove_function)(dest, src, size);