tests: clean up compat test workarounds (#7097)

- Cleanup from
https://github.com/neondatabase/neon/pull/7040#discussion_r1521120263 --
in that PR, we needed to let compat tests manually register a node,
because it would run an old binary that doesn't self-register.
- Cleanup vectored get config workaround
- Cleanup a log allow list for which the underlying log noise has been
fixed.

test_runner/fixtures/neon_fixtures.py

@@ -520,9 +520,9 @@ class NeonEnvBuilder:
         self.env = NeonEnv(self)
         return self.env
 
-    def start(self, register_pageservers=False):
+    def start(self):
         assert self.env is not None, "environment is not already initialized, call init() first"
-        self.env.start(register_pageservers=register_pageservers)
+        self.env.start()
 
     def init_start(
         self,
@@ -1115,8 +1115,8 @@ class NeonEnv:
         log.info(f"Config: {cfg}")
         self.neon_cli.init(cfg, force=config.config_init_force)
 
-    def start(self, register_pageservers=False):
-        # storage controller starts first, so that pageserver /re-attach calls don't
+    def start(self):
+        # Storage controller starts first, so that pageserver /re-attach calls don't
         # bounce through retries on startup
         self.storage_controller.start()
 
@@ -1127,11 +1127,6 @@ class NeonEnv:
         # reconcile.
         wait_until(30, 1, storage_controller_ready)
 
-        if register_pageservers:
-            # Special case for forward compat tests, this can be removed later.
-            for pageserver in self.pageservers:
-                self.storage_controller.node_register(pageserver)
-
         # Start up broker, pageserver and all safekeepers
         futs = []
         with concurrent.futures.ThreadPoolExecutor(

test_runner/regress/test_compatibility.py

@@ -226,10 +226,6 @@ def test_forward_compatibility(
     )
 
     try:
-        # TODO: remove this once the previous pageserrver version understands
-        # the 'get_vectored_impl' config
-        neon_env_builder.pageserver_get_vectored_impl = None
-
         neon_env_builder.num_safekeepers = 3
         neon_local_binpath = neon_env_builder.neon_binpath
         env = neon_env_builder.from_repo_dir(
@@ -238,15 +234,11 @@ def test_forward_compatibility(
             pg_distrib_dir=compatibility_postgres_distrib_dir,
         )
 
-        # TODO: remove this workaround after release-5090 is no longer the most recent release.
-        # There was a bug in that code that generates a warning in the storage controller log.
-        env.storage_controller.allowed_errors.append(".*no tenant_shard_id specified.*")
-
         # Use current neon_local even though we're using old binaries for
         # everything else: our test code is written for latest CLI args.
         env.neon_local_binpath = neon_local_binpath
 
-        neon_env_builder.start(register_pageservers=True)
+        neon_env_builder.start()
 
         check_neon_works(
             env,