Revert "fstab: allow unlocked devices to boot with AVB test key"

This reverts commit c13cd03ccf360755bcebaa0df94427a3ac81217e.

Reason for revert: Let's go through a proper security review for this.

Bug: 306264015
Change-Id: I51fe3f32f8a4ec92cb2d38869568a51dc2522bb4
1 file changed