VM: Reland Inline instance object hash code into object header on 64bit.

runtime/vm/intrinsifier_arm.cc

Index: runtime/vm/intrinsifier_arm.cc
diff --git a/runtime/vm/intrinsifier_arm.cc b/runtime/vm/intrinsifier_arm.cc
index 365be150f9ea9dd9d3039c17db3caaf229ac0dd8..905dfcacb5c2088883eaa1c839c8bb60e992b0a6 100644
--- a/runtime/vm/intrinsifier_arm.cc
+++ b/runtime/vm/intrinsifier_arm.cc
@@ -1875,6 +1875,16 @@ void Intrinsifier::StringBaseSubstringMatches(Assembler* assembler) {
 }
 
 
+void Intrinsifier::Object_getHash(Assembler* assembler) {
+  UNREACHABLE();
+}
+
+
+void Intrinsifier::Object_setHash(Assembler* assembler) {
+  UNREACHABLE();
+}
+
+
 void Intrinsifier::StringBaseCharAt(Assembler* assembler) {
   Label fall_through, try_two_byte_string;