Ensure we get native stack traces from libcorkscrew for CheckJNI aborts.

Change-Id: Ic4cbf457b64c645588a55aee659b7219a687b9ac
diff --git a/src/check_jni.cc b/src/check_jni.cc
index b8a492d..8efdd1b 100644
--- a/src/check_jni.cc
+++ b/src/check_jni.cc
@@ -54,6 +54,7 @@
   if (vm->check_jni_abort_hook != NULL) {
     vm->check_jni_abort_hook(os.str());
   } else {
+    self->SetState(Thread::kNative); // Ensure that we get a native stack trace for this thread.
     LOG(FATAL) << os.str();
   }
 }