Move AHardwareBuffer_getNativeHandle to VNDK

This was added to the NDK only because we didn't have a way to do
VNDK-only declarations. Now we do.

Bug: 34050596
Test: make checkbuild
Change-Id: I039fccfd9f29c5cc960e7691f0baa70101659949
diff --git a/libs/nativewindow/tests/c_compatibility.c b/libs/nativewindow/tests/c_compatibility.c
index a0dfdf9..befd88f 100644
--- a/libs/nativewindow/tests/c_compatibility.c
+++ b/libs/nativewindow/tests/c_compatibility.c
@@ -16,6 +16,7 @@
 
 #include <android/hardware_buffer.h>
 #include <android/native_window.h>
+#include <vndk/hardware_buffer.h>
 #include <vndk/window.h>
 
 // this checks that all these headers are C-compatible