Add input-related file to all host builds of runtime

This makes various input-related files part of all builds of
libandroid_runtime, including host builds. In particular, this makes
android_view_MotionEvent jni bindings work for host builds.
This also rename LayoutlibLoader to HostRuntime as it may end up being
used by more than Layoutlib.

Bug: 322360037
Test: build libandroid_runtime on host
Change-Id: I5e5f57a2bf102c7ac5d96e16bd22f4f71e35e1ba