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

src/lithium-codegen.cc

Index: src/lithium-codegen.cc
diff --git a/src/lithium-codegen.cc b/src/lithium-codegen.cc
index eebe1dfde52602961ede8d53c0049b7ba70aff6d..ea04f358713bb17404cc9c228f3eb1ea082b2c02 100644
--- a/src/lithium-codegen.cc
+++ b/src/lithium-codegen.cc
@@ -139,7 +139,7 @@ void LCodeGenBase::Comment(const char* format, ...) {
   // issues when the stack allocated buffer goes out of scope.
   size_t length = builder.position();
   Vector<char> copy = Vector<char>::New(static_cast<int>(length) + 1);
-  OS::MemCopy(copy.start(), builder.Finalize(), copy.length());
+  MemCopy(copy.start(), builder.Finalize(), copy.length());
   masm()->RecordComment(copy.start());
 }