Bring periodic perf tests on GitHub back (#2037)

* test/fixtures: fix DeprecationWarning
* workflows/benchmarking: increase timeout
* test: switch pgbench to default(simple) query mode
* test/performance: ensure we don't have tables that we're creating
* workflows/pg_clients: remove unused env var
* workflows/benchmarking: change platform name

test_runner/performance/test_wal_backpressure.py

@@ -116,7 +116,6 @@ def start_pgbench_simple_update_workload(env: PgCompare, duration: int):
             '-c10',
             '-N',
             f'-T{duration}',
-            '-Mprepared',
             env.pg.connstr(options="-csynchronous_commit=off")
         ])
         env.flush()