Return NOT_A_PROBABILITY in getProbability for inalid dictionary.

Bug: 9682742
Change-Id: Ifad4b9811bb5e1a94aed59eba7aedcdb6da5cf9c
diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index 2b8dbbc..6e1b80e 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -201,7 +201,7 @@
 static jint latinime_BinaryDictionary_getProbability(JNIEnv *env, jclass clazz, jlong dict,
         jintArray word) {
     Dictionary *dictionary = reinterpret_cast<Dictionary *>(dict);
-    if (!dictionary) return 0;
+    if (!dictionary) return NOT_A_PROBABILITY;
     const jsize wordLength = env->GetArrayLength(word);
     int codePoints[wordLength];
     env->GetIntArrayRegion(word, 0, wordLength, codePoints);