REGTESTS: checks: make 4be_1srv_health_checks more reliable

REGTESTS: checks: make 4be_1srv_health_checks more reliable

This test occasionally fails on the Travis CI tests because the
"in progress" bit is sometimes still set (or set again) in the show
servers state output and is not expected in all regexes (some do
already cover it), like in this one :

   https://travis-ci.com/haproxy/haproxy/jobs/221324920

Let's extend the remaining ones to accept this as well. Other tests
do not seem affected as they only expect sequences of digits there.