selftest: Remove duplicate run of rpc.samr tests against ad_dc as "samba3"

selftest: Remove duplicate run of rpc.samr tests against ad_dc as "samba3"

Running these tests twice is a waste (sorry, thas was my choice when
merging s3 and s4 to just run all the tests against the AD DC) and
more importantly means that tests are run in "samba3" mode against
the AD DC, making it difficult to change the tests to expect a different
behaivour against the AD DC compared to the NT4 DC.

To assure that we have not lost tests, I ran:
grep command st/subunit | grep ad_dc| cut -f 2 -d\" | cut -f 2- -d. | sort | uniq -c

The output is:
--- /tmp/2 2022-02-11 21:00:54.033610748 +1300
+++ /tmp/now 2022-02-11 21:01:13.849823721 +1300
@@ -1,32 +1,21 @@
-      2 rpc.samr.
-      2 rpc.samr.handletype.
       2 rpc.samr.handletype with .
       2 rpc.samr.handletype with bigendian.
       2 rpc.samr.handletype with validate.
-      2 rpc.samr.large-dc.
       2 rpc.samr.large-dc on ncacn_np with .
-      2 rpc.samr.machine.auth.
       2 rpc.samr.machine.auth with .
       2 rpc.samr.machine.auth with bigendian.
       2 rpc.samr.machine.auth with validate.
       2 rpc.samr on ncacn_np with .
-      2 rpc.samr.passwords.
-      2 rpc.samr.passwords.badpwdcount.
       2 rpc.samr.passwords.badpwdcount on ncacn_np with .
       2 rpc.samr.passwords.lockout on ncacn_np with .
       2 rpc.samr.passwords on ncacn_np with .
-      2 rpc.samr.passwords.pwdlastset.
       2 rpc.samr.passwords.pwdlastset on ncacn_np with .
       2 rpc.samr.passwords.validate on ncacn_ip_tcp with bigendian.
       2 rpc.samr.passwords.validate on ncacn_ip_tcp with seal,padcheck.
       2 rpc.samr.passwords.validate on ncacn_ip_tcp with validate.
-      2 rpc.samr.passwords.validate over ncacn_ip_tcp .
-      2 rpc.samr.priv.
       2 rpc.samr.priv with .
       2 rpc.samr.priv with bigendian.
       2 rpc.samr.priv with validate.
-      2 rpc.samr.users.
       2 rpc.samr.users on ncacn_np with .
-      2 rpc.samr.users.privileges.
       2 rpc.samr.users.privileges on ncacn_np with .
       4 tests.dcerpc.samr_change_password.

It is clear that the tests are all still being run at least once against the AD DC.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>