Tweaks to SimpleMap
Tweaks to SimpleMap

Now uses a custom representation for sizes 4 and over. This improves on the previous representation in terms of immutable.Map because it is more efficient for smaller sizes and keeps orderedness. Being ordered is important for making things replayable.

lampepfl/dotty,AlexSikia/dotty,dotty-staging/dotty,auvik/dotty,DarkDimius/dotty,folone/dotty,dotty-staging/dotty,vsalvis/dotty,VladimirNik/dotty,sjrd/dotty,vsalvis/dotty,spetz911/dotty,lampepfl/dotty,reactormonk/dotty,sjrd/dotty,reactormonk/dotty,auvik/dotty,dotty-staging/dotty,lampepfl/dotty,lampepfl/dotty,angi2/dotty,angi2/dotty,sjrd/dotty,densh/dotty,som-snytt/dotty,densh/dotty,som-snytt/dotty,som-snytt/dotty,yusuke2255/dotty,VladimirNik/dotty,svalaskevicius/dotty,lampepfl/dotty,som-snytt/dotty,dotty-staging/dotty,AlexSikia/dotty,dotty-staging/dotty,yusuke2255/dotty,folone/dotty,sjrd/dotty,som-snytt/dotty,svalaskevicius/dotty,sjrd/dotty,spetz911/dotty