Move OS::MemCopy and OS::MemMove out of platform to utils

src/execution.cc

Index: src/execution.cc
diff --git a/src/execution.cc b/src/execution.cc
index f16ee05aca8b9003b9a08f13a3e116f72af6c314..0b8a04cb73e40983643fdfb589e686b3b617c657 100644
--- a/src/execution.cc
+++ b/src/execution.cc
@@ -380,7 +380,7 @@ bool StackGuard::CheckAndClearInterrupt(InterruptFlag flag,
 
 char* StackGuard::ArchiveStackGuard(char* to) {
   ExecutionAccess access(isolate_);
-  OS::MemCopy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
+  MemCopy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
   ThreadLocal blank;
 
   // Set the stack limits using the old thread_local_.
@@ -397,8 +397,7 @@ char* StackGuard::ArchiveStackGuard(char* to) {
 
 char* StackGuard::RestoreStackGuard(char* from) {
   ExecutionAccess access(isolate_);
-  OS::MemCopy(
-      reinterpret_cast<char*>(&thread_local_), from, sizeof(ThreadLocal));
+  MemCopy(reinterpret_cast<char*>(&thread_local_), from, sizeof(ThreadLocal));
   isolate_->heap()->SetStackLimits();
   return from + sizeof(ThreadLocal);
 }