ADBDEV-8171: Turn off the orca optimizer in gprestore

[KnightMurloc]

When planning queries from gprestore, Orca trying to plan a query, but it almost
always fails due to the lack of support for planning queries which containing
system tables. At the same time, the start of Orca planning takes a considerable
amount of time. This is especially noticeable when restoring statistics.

This patch disables orca in gprestore sessions.

[RekGRpth]

When planning queries from gprestore, Orca trying to plan a query, but it almost
always fails due to the lack of support for planning queries which containing
system tables. At the same time, the start of Orca planning takes a considerable
amount of time.

Is gpbackup subject to the same problem?

[KnightMurloc]

Is gpbackup subject to the same problem?

Maybe. But gpbackup performs fewer queries so the problem should be less noticeable.

[hilltracer]

I've repeated experiments like I did in the last PR

The results for restoring all data with statistics:

GPDB 6	without patch	9m41.577s
GPDB 6	with patch	2m49.590s
GPDB 7	without patch	6m27.511s
GPDB 7	with patch	2m12.082s

I think it's a very good result.

I faced a problem on GPDB 7, sometimes restore fails with message.
I see error like:

20250905:12:44:30 gprestore:gpadmin:gpdb7u:872488-[CRITICAL]:-ERROR: duplicate key value violates unique constraint "pg_statistic_relid_att_inh_index" (SQLSTATE 23505)

But it looks like the problem isn't related to the current patch, because I see it even without patch.
I will create the issue about it.