shell: neverallow access to 'proc' label.

Added access to proc_uptime and proc_asound to address these denials:

avc: denied { read } for name="uptime" dev="proc" ino=4026532080
scontext=u:r:shell:s0 tcontext=u:object_r:proc_uptime:s0 tclass=file
permissive=1

avc: denied { getattr } for path="/proc/asound/version" dev="proc"
ino=4026532017 scontext=u:r:shell:s0 tcontext=u:object_r:proc_asound:s0
tclass=file permissive=1

Bug: 65643247
Test: device boots with no denial from 'shell' domain.
Test: lsmod, ps, top, netstat
Test: No denials triggered from CtsSecurityHostTestCases
Test: external/toybox/run-tests-on-android.sh does not pass, but triggers
no denials from 'shell' domain to 'proc' type.

Change-Id: Ia4c26fd616e33e5962c6707a855dc24e338ec153

private/domain.te

@@ -27,7 +27,6 @@ full_treble_only(`
     -dumpstate
     -platform_app
     -priv_app
-    -shell
     -system_app
     -vold
     -vendor_init

public/shell.te

@@ -107,16 +107,21 @@ hwbinder_use(shell)
 allow shell hwservicemanager:hwservice_manager list;
 
 # allow shell to look through /proc/ for lsmod, ps, top, netstat.
-r_dir_file(shell, proc)
 r_dir_file(shell, proc_net)
-allow shell proc_filesystems:file r_file_perms;
-allow shell proc_interrupts:file r_file_perms;
-allow shell proc_meminfo:file r_file_perms;
-allow shell proc_modules:file r_file_perms;
-allow shell proc_stat:file r_file_perms;
-allow shell proc_timer:file r_file_perms;
-allow shell proc_version:file r_file_perms;
-allow shell proc_zoneinfo:file r_file_perms;
+
+allow shell {
+  proc_asound
+  proc_filesystems
+  proc_interrupts
+  proc_meminfo
+  proc_modules
+  proc_stat
+  proc_timer
+  proc_uptime
+  proc_version
+  proc_zoneinfo
+}:file r_file_perms;
+
 r_dir_file(shell, cgroup)
 allow shell domain:dir { search open read getattr };
 allow shell domain:{ file lnk_file } { open read getattr };