Add test to verify page size of Microdroid VM

Also fix the x86_64 microdroid_16k. Unfortunately passing the
`page_shift = 14` option in the bootconfig doesn't enable 16k emulation,
so we need to pass the option in the kernel cmdline until support for
bootconfig is implemented in the kernel.

Bug: 333730505
Test: atest MicrodroidTests
Change-Id: I35375ad272b4ff91c37a9a69658a17045a4a7ac8
diff --git a/tests/testapk/src/native/testbinary.rs b/tests/testapk/src/native/testbinary.rs
index 85b411e..e479342 100644
--- a/tests/testapk/src/native/testbinary.rs
+++ b/tests/testapk/src/native/testbinary.rs
@@ -123,6 +123,9 @@
     fn getMountFlags(&self, _: &str) -> BinderResult<i32> {
         unimplemented()
     }
+    fn getPageSize(&self) -> BinderResult<i32> {
+        unimplemented()
+    }
     fn requestCallback(&self, _: &Strong<dyn IAppCallback + 'static>) -> BinderResult<()> {
         unimplemented()
     }