According to source.android.com switching SELinux to permissive mode can be done via setting:

BOARD_KERNEL_CMDLINE := androidboot.selinux=permissive

or

BOARD_BOOTCONFIG := androidboot.selinux=permissive

And it works well for HiKey960 devboard for hikey960-userdebug target (what was already discussed here https://stackoverflow.com/a/65992376/5130269) but for AOSP standard emulator targets, like aosp_x86-eng or aosp_car_x86-userdebug it doesn't work, why?