Binder: disambiguate unlinkToDeath error

BpBinder may return OK, DEAD_OBJECT, or NAME_NOT_FOUND for this
operation, but BBinder returns INVALID_OPERATION, and subclasses may
return other errors. In at least one bug, the resolution of this
ambiguity would help direct debugging.

Bug: 180891878
Test: N/A

Change-Id: I109a09788d3075e7c594445a6f3649ade109b5c2

core/jni/android_util_Binder.cpp

@@ -1516,7 +1516,9 @@ static jboolean android_os_BinderProxy_unlinkToDeath(JNIEnv* env, jobject obj,
             res = JNI_TRUE;
         } else {
             jniThrowException(env, "java/util/NoSuchElementException",
-                              "Death link does not exist");
+                              base::StringPrintf("Death link does not exist (%s)",
+                                                 statusToString(err).c_str())
+                                      .c_str());
         }
     }