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

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 6cdd4a953088bfe013535f9a8c2a7fb3efddc6bc..e8d3e713795e360d04467fc06b1e4f3846830bbe 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -172,15 +172,11 @@ BUILTIN(EmptyFunction) {
 }
 
 
-static void MoveDoubleElements(FixedDoubleArray* dst,
-                               int dst_index,
-                               FixedDoubleArray* src,
-                               int src_index,
-                               int len) {
+static void MoveDoubleElements(FixedDoubleArray* dst, int dst_index,
+                               FixedDoubleArray* src, int src_index, int len) {
   if (len == 0) return;
-  OS::MemMove(dst->data_start() + dst_index,
-              src->data_start() + src_index,
-              len * kDoubleSize);
+  MemMove(dst->data_start() + dst_index, src->data_start() + src_index,
+          len * kDoubleSize);
 }