Revert "libbinder: Consider VNDK_APEX as vendor stable"

This reverts commit 6b92a6d3830a0f428adf0a2c7ecc53d52c37aa90.

Reason for revert: some targets are broken

Test: m
Bug: 142773030
Change-Id: I6109ecf7a73ea77de1e64981d21329c8c3119bcf
3 files changed