Slow test test_https_conn_post_handshake on Linux

[alfredh]

Platform: Debian 12

The test test_https_conn_post_handshake is very slow around 1.8 seconds.

alfredh@debian:~/git/re$ ./test/retest -p
retest: libre version 3.17.0 (x86_64/Linux)
using async polling method 'epoll'

sorted by average timing (slowest on top):
test_https_conn_post_handshake    : 1844058.00 usec
test_https_loop                   :  884029.00 usec
test_https_large_body             :  428247.66 usec
test_http_conn_large_body         :  320060.66 usec
test_http_large_body              :  318892.66 usec
test_rtmps_publish                :  136004.33 usec
test_tls_ec                       :   95969.33 usec
test_rtmp_publish                 :   88003.33 usec
test_rtmp_play                    :   87999.66 usec
test_tls_cli_conn_change_cert     :   51991.33 usec
test_tls_sni                      :   51985.66 usec
test_tls                          :   48002.33 usec
test_tls_session_reuse_tls_v12    :   48000.00 usec
test_json_file                    :   12254.00 usec
test_vid                          :   11798.87 usec
test_http_conn                    :   10861.77 usec
test_http_loop                    :   10654.66 usec
test_trice_loop                   :    8720.18 usec

alfredh@debian:~/git/re$ time ./test/retest -v -r test_https_conn_post_handshake
single testcase: test_https_conn_post_handshake
retest: libre version 3.17.0 (x86_64/Linux)
using async polling method 'epoll'
using datapath './test/data'
regular tests:       OK

real	0m1.857s
user	0m0.170s
sys	0m0.016s

[cspiel1]

We try to have a look on this soon. I talk with @fAuernigg. We can test on Ubuntu and Arch.