tests/ipfw: Update regression tests to match new 32-bit size rule numbers

Commit 4a77657cbc01 increased the size of several opcodes to ipfw_insn_u32.

Approved by: ae
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D52876

(cherry picked from commit 01d5a6f30ce8f5006bd9d5528a487ef4d79c48c3)