patterns.py can't discriminate between VU# and JVNVU#

[ahouseholder]

Describe the bug

The code as is will think that a JVNVU# should be a VU#. But JVNVU# has a different structure and we should have distinct patterns for it.

Expected behavior

Strings matching \bVU# should be parsed correctly and separately from strings matching \bJVNVU#

Additional context

This problem also exists in CERTCC/git_vul_driller#3