Remove thread specific seed code.

Hasn't been used since 2017, so time to cleanup

added cleanup code health labels

requested review from @bvandenbroucke

assigned to @matthieu

@dc-rope1 just looking at some of your changes and noticed this. These pthread calls are another way get things like the threadpool id down to the threads. @matthieu removed the getspecific call a number of years ago.

approved this merge request

approved this merge request

merged

mentioned in commit 66109803