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/code_generator_arm_vixl.h b/compiler/optimizing/code_generator_arm_vixl.h
index 8f3d41c..23d05ae 100644
--- a/compiler/optimizing/code_generator_arm_vixl.h
+++ b/compiler/optimizing/code_generator_arm_vixl.h
@@ -677,7 +677,7 @@
                                              Location ref,
                                              vixl::aarch32::Register obj,
                                              uint32_t offset,
-                                             Location temp,
+                                             Location maybe_temp,
                                              bool needs_null_check);
   // Fast path implementation of ReadBarrier::Barrier for a heap
   // reference array load when Baker's read barriers are used.