Improve FastCloneShallowArray/ObjectStubs with VFP copying on ARM

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
===================================================================
--- src/x64/code-stubs-x64.cc	(revision 12502)
+++ src/x64/code-stubs-x64.cc	(working copy)
@@ -300,6 +300,11 @@
 }
 
 
+int FastCloneShallowArrayStub::MaximumClonedLength() {
+  return 8;
+}
+
+
 static void GenerateFastCloneShallowArrayCommon(
     MacroAssembler* masm,
     int length,
@@ -435,6 +440,11 @@
 }
 
 
+int FastCloneShallowObjectStub::MaximumClonedProperties() {
+  return 6;
+}
+
+
 void FastCloneShallowObjectStub::Generate(MacroAssembler* masm) {
   // Stack layout on entry:
   //