math/py-matplotlib2: Mark BROKEN on 14

• Fails to compile with: ISO C++17 does not allow 'register' storage class specifier
• Although this specific has easy workarounds but it fails at the stage post-stage with the following: ====> Compressing man pages (compress-man) pkill -15 -F /tmp/.xvfb-0.pid pkill: Pidfile `/tmp/.xvfb-0.pid' is empty
  
  The result remains unchanged even with other llvm variants.
• Mark DEPRECATED as upstream support reached EOL during 2020. See the following for more information: https://discourse.matplotlib.org/t/ann-matplotlib-2-2-0-released/20227 Also this does not officially support python3.8 and later.
• Set EXPIRATION_DATE to 2023-09-30

Approved by: portmgr (blanket)
Sponsored by: The FreeBSD Foundation