system_server: drop dalvikcache_data_file execute.

With build/core eaa9d88cf, system_server should not be loading code
from /data.

https://bugs.chromium.org/p/project-zero/issues/detail?id=955

Bug: 37214733
Bug: 31780877
Test: Device boots and no obvious problems.
Test: No collected SELinux denials for build-server generated builds.
Change-Id: I37b1e9e6c4555c937730ab491b6c38801b38ad38

private/system_server.te

@@ -17,11 +17,8 @@ allow system_server zygote_tmpfs:file read;
 
 # For art.
 allow system_server dalvikcache_data_file:dir r_dir_perms;
-allow system_server dalvikcache_data_file:file { r_file_perms execute };
-userdebug_or_eng(`
-  # Report dalvikcache_data_file:file execute violations.
-  auditallow system_server dalvikcache_data_file:file execute;
-')
+allow system_server dalvikcache_data_file:file r_file_perms;
+
 # When running system server under --invoke-with, we'll try to load the boot image under the
 # system server domain, following links to the system partition.
 with_asan(`allow system_server dalvikcache_data_file:lnk_file r_file_perms;')

public/domain.te

@@ -355,7 +355,6 @@ neverallow {
     -dumpstate
     -shell
     userdebug_or_eng(`-su')
-    -system_server
     -webview_zygote
     -zygote
 } {