Implement Reference.getReferent() intrinsic.

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing --jit
Test: aosp_blueline-userdebug boots.
Test: run-gtests.sh
Test: testrunner.py --target --optimizing --jit
Bug: 170286013
Change-Id: I4762f7c1cf3d61de2215ec8f1d14be80289c2372
diff --git a/compiler/optimizing/intrinsics.h b/compiler/optimizing/intrinsics.h
index cc26e41..a0f9420 100644
--- a/compiler/optimizing/intrinsics.h
+++ b/compiler/optimizing/intrinsics.h
@@ -136,6 +136,10 @@
   static IntegerValueOfInfo ComputeIntegerValueOfInfo(
       HInvoke* invoke, const CompilerOptions& compiler_options);
 
+  static MemberOffset GetReferenceDisableIntrinsicOffset();
+  static MemberOffset GetReferenceSlowPathEnabledOffset();
+  static void CreateReferenceGetReferentLocations(HInvoke* invoke, CodeGenerator* codegen);
+
  protected:
   IntrinsicVisitor() {}