pagebench-based GetPage@LSN performance test (#6214)

scripts/ps_ec2_setup_instance_store

@@ -39,6 +39,9 @@ SETUP COMPLETE
 To run your local neon.git build on the instance store volume,
 run the following commands from the top of the neon.git checkout
 
+    # raise file descriptor limit of your shell and its child processes
+    sudo prlimit -p $$ --nofile=800000:800000
+
     # test suite run
     export TEST_OUTPUT="$TEST_OUTPUT"
     DEFAULT_PG_VERSION=15 BUILD_TYPE=release ./scripts/pytest test_runner/performance/test_latency.py