ART: Fix 466-get-live-vreg for read barrier.

With the read barrier, the test is actually compiled but it
runs interpreted, so the vreg is successfully retrieved.
Fix the stack visitor to check if we have a compiled frame
before checking if the method is "Optimized".

Change-Id: I600eb7b5c0c2be1b9617e4d05401a711dac01738
diff --git a/test/466-get-live-vreg/get_live_vreg_jni.cc b/test/466-get-live-vreg/get_live_vreg_jni.cc
index 9b32fc3..e3e0091 100644
--- a/test/466-get-live-vreg/get_live_vreg_jni.cc
+++ b/test/466-get-live-vreg/get_live_vreg_jni.cc
@@ -42,7 +42,7 @@
     } else if (m_name.compare("testIntervalHole") == 0) {
       found_method_ = true;
       uint32_t value = 0;
-      if (m->IsOptimized(sizeof(void*))) {
+      if (GetCurrentQuickFrame() != nullptr && m->IsOptimized(sizeof(void*))) {
         CHECK_EQ(GetVReg(m, 0, kIntVReg, &value), false);
       } else {
         CHECK(GetVReg(m, 0, kIntVReg, &value));