Random allocation could pick 33646 = admin.port (23646) + GrpcPortOffset.
weed mini reserves that as Admin's gRPC port even when the test only
overrides Master/Filer/S3/Iceberg, so the explicit Filer flag failed
with "reserved for gRPC calculation" and TestRisingWaveIcebergCatalog
flaked. Pre-seed the reserved set with every mini default HTTP port
plus its +10000 offset so a random pick (or its own gRPC offset) cannot
land on a service the caller left at its default.
4f17c6661a