Sometimes isolation_metadata_sync_deadlock fails in CI like this:
```diff
diff -dU10 -w /__w/citus/citus/src/test/regress/expected/isolation_metadata_sync_deadlock.out /__w/citus/citus/src/test/regress/results/isolation_metadata_sync_deadlock.out
--- /__w/citus/citus/src/test/regress/expected/isolation_metadata_sync_deadlock.out.modified 2023-11-01 16:03:15.090199229 +0000
+++ /__w/citus/citus/src/test/regress/results/isolation_metadata_sync_deadlock.out.modified 2023-11-01 16:03:15.098199312 +0000
@@ -110,10 +110,14 @@
t
(1 row)
step s2-stop-connection:
SELECT stop_session_level_connection_to_node();
stop_session_level_connection_to_node
-------------------------------------
(1 row)
+
+teardown failed: ERROR: localhost:57638 is a metadata node, but is out of sync
+HINT: If the node is up, wait until metadata gets synced to it and try again.
+CONTEXT: SQL statement "SELECT master_remove_distributed_table_metadata_from_workers(v_obj.objid, v_obj.schema_name, v_obj.object_name)"
```
Source:
https://github.com/citusdata/citus/actions/runs/6721938040/attempts/1#summary-18268946448
To fix this we now wait for the metadata to be fully synced to all
nodes at the start of the teardown steps.
(cherry picked from commit a6e86884f6)
Use Citus helper UDFs by default in iso tests
PostgreSQL isolation test infrastructure uses some UDFs to detect
whether concurrent sessions block each other. Citus implements
alternatives to that UDF so that we are able to detect and report
distributed transactions that get blocked on the worker nodes as well.
We needed to explicitly replace PG helper functions with Citus
implementations in each isolation file. Now we replace them by default.
With this commit we've started to propagate sequences and shell
tables within the object dependency resolution. So, ensuring any
dependencies for any object will consider shell tables and sequences
as well. Separate logics for both shell tables and sequences have
been removed.
Since both shell tables and sequences logic were implemented as a
part of the metadata handling before that logic, we were propagating
them while syncing table metadata. With this commit we've divided
metadata (which means anything except shards thereafter) syncing
logic into multiple parts and implemented it either as a part of
ActivateNode. You can check the functions called in ActivateNode
to check definition of different metadata.
Definitions of start_metadata_sync_to_node and citus_activate_node
have also been updated. citus_activate_node will basically create
an active node with all metadata and reference table shards.
start_metadata_sync_to_node will be same with citus_activate_node
except replicating reference tables. stop_metadata_sync_to_node
will remove all the metadata. All of those UDFs need to be called
by superuser.