Define a symbole file for libvm_payload, and request stubs. Make sure
the clients build against the stubs.
Mark the implementation as not required, to prevent the missing
dependencies check triggering; it is actually present at runtime
inside Microdroid.
Bug: 243512108
Bug: 255920361
Test: atest MicrodroidTests
Test: composd-cmd test-compile
Change-Id: I78c33b6fba706fd0e52435ac13d02a25171862f1
Alan Stokes