Fix cache lookup hazards introduced by ff9618e82a.

ff9618e82a introduced has_partition_ancestor_privs(), which is used
to check whether a user has MAINTAIN on any partition ancestors.
This involves syscache lookups, and presently this function does
not take any relation locks, so it is likely subject to the same
kind of cache lookup failures that were fixed by 19de0ab23c.

To fix this problem, this commit partially reverts ff9618e82a.
Specifically, it removes the partition-related changes, including
the has_partition_ancestor_privs() function mentioned above.  This
means that MAINTAIN on a partitioned table is no longer sufficient
to perform maintenance commands on its partitions.  This is more
like how privileges for maintenance commands work on supported
versions.  Privileges are checked for each partition, so a command
that flows down to all partitions might refuse to process them
(e.g., if the current user doesn't have MAINTAIN on the partition).

In passing, adjust a few related comments and error messages, and
add a test for the privilege checks for CLUSTER on a partitioned
table.

Reviewed-by: Michael Paquier, Jeff Davis
Discussion: https://postgr.es/m/20230613211246.GA219055%40nathanxps13

doc/src/sgml/ref/analyze.sgml

@@ -190,10 +190,7 @@ ANALYZE [ VERBOSE ] [ <replaceable class="parameter">table_and_columns</replacea
    analyze all tables in their databases, except shared catalogs.
    (The restriction for shared catalogs means that a true database-wide
    <command>ANALYZE</command> can only be performed by superusers and roles
-   with privileges of <literal>pg_maintain</literal>.)  If a role has
-   permission to <command>ANALYZE</command> a partitioned table, it is also
-   permitted to <command>ANALYZE</command> each of its partitions, regardless
-   of whether the role has the aforementioned privileges on the partition.
+   with privileges of <literal>pg_maintain</literal>.)
    <command>ANALYZE</command> will skip over any tables that the calling user
    does not have permission to analyze.
   </para>

doc/src/sgml/ref/cluster.sgml

@@ -137,10 +137,7 @@ CLUSTER [VERBOSE]
     on the table or be the table's owner, a superuser, or a role with
     privileges of the
     <link linkend="predefined-roles-table"><literal>pg_maintain</literal></link>
-    role.  If a role has permission to <command>CLUSTER</command> a partitioned
-    table, it is also permitted to <command>CLUSTER</command> each of its
-    partitions, regardless of whether the role has the aforementioned
-    privileges on the partition.  <command>CLUSTER</command> will skip over any
+    role.  <command>CLUSTER</command> will skip over any
     tables that the calling user does not have permission to cluster.
    </para>
 

doc/src/sgml/ref/lock.sgml

@@ -177,10 +177,7 @@ LOCK [ TABLE ] [ ONLY ] <replaceable class="parameter">name</replaceable> [ * ]
     MODE</literal> (or a less-conflicting mode as described in <xref
     linkend="explicit-locking"/>) is permitted. If a user has
     <literal>SELECT</literal> privileges on the table, <literal>ACCESS SHARE
-    MODE</literal> is permitted.  If a role has permission to lock a
-    partitioned table, it is also permitted to lock each of its partitions,
-    regardless of whether the role has the aforementioned privileges on the
-    partition.
+    MODE</literal> is permitted.
    </para>
 
    <para>

doc/src/sgml/ref/reindex.sgml

@@ -306,11 +306,7 @@ REINDEX [ ( <replaceable class="parameter">option</replaceable> [, ...] ) ] { DA
    indexes on shared catalogs will be skipped unless the user owns the
    catalog (which typically won't be the case), has privileges of the
    <literal>pg_maintain</literal> role, or has the <literal>MAINTAIN</literal>
-   privilege on the catalog.  If a role has permission to
-   <command>REINDEX</command> a partitioned table, it is also permitted to
-   <command>REINDEX</command> each of its partitions, regardless of whether the
-   role has the aforementioned privileges on the partition.  Of course,
-   superusers can always reindex anything.
+   privilege on the catalog.  Of course, superusers can always reindex anything.
   </para>
 
   <para>

doc/src/sgml/ref/vacuum.sgml

@@ -452,10 +452,7 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] [ ANALYZE ] [ <replaceable class="paramet
     vacuum all tables in their databases, except shared catalogs.
     (The restriction for shared catalogs means that a true database-wide
     <command>VACUUM</command> can only be performed by superusers and roles
-    with privileges of <literal>pg_maintain</literal>.)  If a role has
-    permission to <command>VACUUM</command> a partitioned table, it is also
-    permitted to <command>VACUUM</command> each of its partitions, regardless
-    of whether the role has the aforementioned privileges on the partition.
+    with privileges of <literal>pg_maintain</literal>.)
     <command>VACUUM</command> will skip over any tables that the calling user
     does not have permission to vacuum.
    </para>