ANDROID: binder: add ANDROID_BINDER_IPC_RUST_DUMMY

Rust does not currently support the kernel-hwaddress sanitizer, so
KASAN_SW_TAGS cannot be enabled (other KASAN variants are supported).
This means that when building with --kasan_sw_tags, Rust gets disabled,
and no rust_binder.ko module is built, which causes a build failure as
it's expected to be available as a GKI module.

Provide a new option to build a dummy module called rust_binder.ko that
can be included in KASAN_SW_TAGS builds.

This approach is used because _ARM64_GKI_MODULES_LIST does not currently
support select(), so we cannot remove rust_binder.ko from the list of
expected modules.

Bug: 419603781
Change-Id: I1e24a2f00e1bd38bb60e9ef40c3189e17ef5a687
Signed-off-by: Alice Ryhl <aliceryhl@google.com>