Obviate libbinder_ndk_host_user.

After this, it is no longer required in order to use libbinder_ndk on
host. Following this change, all users will be cleaned up and the
module itself will be removed.

Bug: 211908498
Test: build
Change-Id: I7136472677ada11cc2c0b726cd849cac98d3ee4e
Merged-In: I7136472677ada11cc2c0b726cd849cac98d3ee4e
(cherry picked from commit 619a02a6)