fixup(#7204 / postgres): revert IsPrimaryAlive checks (#7209)

Fix #7204.

https://github.com/neondatabase/postgres/pull/400
https://github.com/neondatabase/postgres/pull/401
https://github.com/neondatabase/postgres/pull/402

These commits never go into prod. Detailed investigation will be posted
in another issue. Reverting the commits so that things can keep running
in prod. This pull request adds the test to start two replicas. It fails
on the current main https://github.com/neondatabase/neon/pull/7210 but
passes in this pull request.

---------

Signed-off-by: Alex Chi Z <chi@neon.tech>

test_runner/regress/test_hot_standby.py

@@ -84,3 +84,21 @@ def test_hot_standby(neon_simple_env: NeonEnv):
     # clean up
     if slow_down_send:
         sk_http.configure_failpoints(("sk-send-wal-replica-sleep", "off"))
+
+
+def test_2_replicas_start(neon_simple_env: NeonEnv):
+    env = neon_simple_env
+
+    with env.endpoints.create_start(
+        branch_name="main",
+        endpoint_id="primary",
+    ) as primary:
+        time.sleep(1)
+        with env.endpoints.new_replica_start(
+            origin=primary, endpoint_id="secondary1"
+        ) as secondary1:
+            with env.endpoints.new_replica_start(
+                origin=primary, endpoint_id="secondary2"
+            ) as secondary2:
+                wait_replica_caughtup(primary, secondary1)
+                wait_replica_caughtup(primary, secondary2)

test_runner/regress/test_replication_start.py

@@ -1,7 +1,9 @@
+import pytest
 from fixtures.log_helper import log
 from fixtures.neon_fixtures import NeonEnv, wait_replica_caughtup
 
 
+@pytest.mark.xfail
 def test_replication_start(neon_simple_env: NeonEnv):
     env = neon_simple_env
 

vendor/revisions.json

@@ -1,5 +1,5 @@
 {
-  "postgres-v16": "111e82c45d79728fdd3a4816605378c3cc5cfe84",
-  "postgres-v15": "af9ab67bc80afd94e4eb11c34f50c0a29c37eb1b",
-  "postgres-v14": "c5d920a7d9e9cbeb62b6c46f292db08162763f68"
+  "postgres-v16": "3946b2e2ea71d07af092099cb5bcae76a69b90d6",
+  "postgres-v15": "e7651e79c0c27fbddc3c724f5b9553222c28e395",
+  "postgres-v14": "748643b4683e9fe3b105011a6ba8a687d032cd65"
 }