system_server: Delete system_file:file execute_no_trans;

auditallow has been in place since Apr 2016
(f84b7981) and no SELinux denials have
been generated / collected. Remove unused functionality.

Test: Device boots with no problems.
Test: no SELinux denials of this type collected.
Bug: 28035297
Change-Id: I52414832abb5780a1645a4df723c6f0c758eb5e6