Removed static from CachingSeedCleanerByHitPosition::good

The function local static was to a class with no member data and
no virtual functions. Since it had no state there was no need to make
it static and making it static meant the compiler had to use lots of
extra machine code. Removing the static and making it const makes the
code easier to reason about and avoids complaints from the static
analyzer.
Merge pull request #3792 from Dr15Jones/removeStaticInCachingSeedCleanerByHitPosition

Multithreading -- Removed static from CachingSeedCleanerByHitPosition::good