Allow init to mount on bionic libs and the dynamic linker

In order to use the bionic libs and the dynamic linker from the runtime
APEX for all processes that are started after the APEX is activated, the
paths /system/lib/{libc.so|libm.so|libdl.so} and /system/bin/linker are
bind-mounted to the corresponding bionic libs and the dynamic linker
in the runtime APEX.

This bind mount allows us to keep other part of the platform and the
tests having implicit assumption that bionic libs are located at
/system/lib and loaded from the default linker namespace.

Bug: 120266448
Test: device boots

Change-Id: Ied611b267d187ee3d75a139c378ee12242d5b8d8

public/init.te

@@ -84,6 +84,9 @@ allow init device:dir mounton;
 # Mount tmpfs on /apex
 allow init apex_mnt_dir:dir mounton;
 
+allow init system_lib_file:file mounton;
+allow init system_linker_exec:file mounton;
+
 # Create and remove symlinks in /.
 allow init rootfs:lnk_file { create unlink };