[9.18] chg: test: Bump max-recursion-queries to 100 in resolver system test

With max-recursion-queries set to 50 the resolver system test was
unstable in the "checking query resolution for a domain with a valid
glueless delegation chain" check as ns1 replied with SERVFAIL.

Closes #4897

Backport of MR !9435

Merge branch 'backport-4897-resolver-ns1-max-recursion-queries-100-9.18' into 'bind-9.18'

See merge request isc-projects/bind9!9441