Don't include AIDL NDK output if not needed

Bug: 302724232
Test: mma
Change-Id: Ibdc5a0f58dd4adb3aaf64b9176b1b6e545318e08
diff --git a/libs/binder/tests/binderRpcTest.cpp b/libs/binder/tests/binderRpcTest.cpp
index 5884dbe..1340ea1 100644
--- a/libs/binder/tests/binderRpcTest.cpp
+++ b/libs/binder/tests/binderRpcTest.cpp
@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
+#ifndef __ANDROID_VENDOR__
+// only used on NDK tests outside of vendor
 #include <aidl/IBinderRpcTest.h>
+#endif
 #include <android-base/stringprintf.h>
 
 #include <chrono>