gt-pl-max on x_linked_* tests

[davemcg]

Is there a reason why this filter has been removed from the x_linked_* tests? This isn't a crucial filter, but I do like to set it for the tests we run.

Gemini 0.19

[brentp]

in our experience, --min-gq is a better filter and less confusing so I didn't add the PL stuff to the new tools.

[davemcg]

Good to know, I may just remove it from my gemini calls for consistency.