quic_tserver_test: Raise the initial timeout limit

quic_tserver_test: Raise the initial timeout limit

There were intermitten failures on the test occasionally and
1s initial limit might be too short.

Fixes #22424

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22475)