native: Cleanup jni usage code

Make the C++ signature consistent with the JNI descriptor by using the
same type as the descriptor whenever possible.

e.g. "()Ljava/lang/String;" should actually be "jstring fn(JNIEnv*,jobject)"
instead of "jobject fn(JNIEnv*,jobject)".

Bug: 35325126
Change-Id: I72318525fc3b18b013b8d6fa604d8dd6b5dd4400
Test: make -j32 test-art-host  # and also manually that it boots
diff --git a/runtime/native/java_lang_reflect_Method.cc b/runtime/native/java_lang_reflect_Method.cc
index b604dc0..4355c06 100644
--- a/runtime/native/java_lang_reflect_Method.cc
+++ b/runtime/native/java_lang_reflect_Method.cc
@@ -82,7 +82,7 @@
 }
 
 static jobject Method_invoke(JNIEnv* env, jobject javaMethod, jobject javaReceiver,
-                             jobject javaArgs) {
+                             jobjectArray javaArgs) {
   ScopedFastNativeObjectAccess soa(env);
   return InvokeMethod(soa, javaMethod, javaReceiver, javaArgs);
 }