test_runner: remove excessive timeouts (#4659)

## Problem

For some tests, we override the default timeout (300s / 5m) with a larger
values like 600s / 10m or even 1800s / 30m, even if it's not required.
I've collected some statistics (for the last 60 days) for tests
duration:

| test | max (s) | p99 (s) | p50 (s) | count |

|-----------------------------------|---------|---------|---------|-------|
| test_hot_standby | 9 | 2 | 2 | 5319 |
| test_import_from_vanilla | 16 | 9 | 6 | 5692 |
| test_import_from_pageserver_small | 37 | 7 | 5 | 5719 |
| test_pg_regress | 101 | 73 | 44 | 5642 |
| test_isolation | 65 | 56 | 39 | 5692 |

A couple of tests that I left with custom 600s / 10m timeout.

| test | max (s) | p99 (s) | p50 (s) | count |

|-----------------------------------|---------|---------|---------|-------|
| test_gc_cutoff | 456 | 224 | 109 | 5694 |
| test_pageserver_chaos | 528 | 267 | 121 | 5712 |

## Summary of changes
- Remove `@pytest.mark.timeout` annotation from several tests

test_runner/regress/test_hot_standby.py

@@ -1,10 +1,8 @@
 import time
 
-import pytest
 from fixtures.neon_fixtures import NeonEnv
 
 
-@pytest.mark.timeout(1800)
 def test_hot_standby(neon_simple_env: NeonEnv):
     env = neon_simple_env
 

test_runner/regress/test_import.py

@@ -23,7 +23,6 @@ from fixtures.types import Lsn, TenantId, TimelineId
 from fixtures.utils import subprocess_capture
 
 
-@pytest.mark.timeout(600)
 def test_import_from_vanilla(test_output_dir, pg_bin, vanilla_pg, neon_env_builder):
     # Put data in vanilla pg
     vanilla_pg.start()
@@ -163,7 +162,6 @@ def test_import_from_vanilla(test_output_dir, pg_bin, vanilla_pg, neon_env_build
     assert endpoint.safe_psql("select count(*) from t") == [(300000,)]
 
 
-@pytest.mark.timeout(600)
 def test_import_from_pageserver_small(pg_bin: PgBin, neon_env_builder: NeonEnvBuilder):
     neon_env_builder.enable_local_fs_remote_storage()
     env = neon_env_builder.init_start()

test_runner/regress/test_pg_regress.py

@@ -3,15 +3,11 @@
 #
 from pathlib import Path
 
-import pytest
 from fixtures.neon_fixtures import NeonEnv, check_restored_datadir_content
 
 
 # Run the main PostgreSQL regression tests, in src/test/regress.
 #
-# This runs for a long time, especially in debug mode, so use a larger-than-default
-# timeout.
-@pytest.mark.timeout(1800)
 def test_pg_regress(
     neon_simple_env: NeonEnv,
     test_output_dir: Path,
@@ -69,9 +65,6 @@ def test_pg_regress(
 
 # Run the PostgreSQL "isolation" tests, in src/test/isolation.
 #
-# This runs for a long time, especially in debug mode, so use a larger-than-default
-# timeout.
-@pytest.mark.timeout(1800)
 def test_isolation(
     neon_simple_env: NeonEnv,
     test_output_dir: Path,