pf tests: Test PR259689

We didn't populate dyncnt/tblcnt, so pfctl -sr -vv might not have the
table element count.

PR: 259689
MFC after: 3 weeks
Sponsored by: Rubicon Communications, LLC ("Netgate")
Differential Revision: https://reviews.freebsd.org/D32893

(cherry picked from commit 2de49deeca0b1377664dee2cd0a43ee7cf6b4bc4)