Properly describe exception

Previously we used DetachCurrentThread which raised a SIGABRT from
within ART. The new approach is to use ExceptionDescribe and exit.

Bug: 20640601

(cherry picked from commit d12065f581)

Change-Id: I00126b678ff296e0076247554af8328fe2767038

core/jni/android_util_Binder.cpp

@@ -200,10 +200,8 @@ static void report_exception(JNIEnv* env, jthrowable excep, const char* msg)
          * that can be made while an exception is pending, so we want to
          * get the VM ptr, throw the exception, and then detach the thread.
          */
-        JavaVM* vm = jnienv_to_javavm(env);
         env->Throw(excep);
-        vm->DetachCurrentThread();
-        sleep(60);
+        env->ExceptionDescribe();
         ALOGE("Forcefully exiting");
         exit(1);
     }