Fix two infinite cycles in transformAfter.
Fix two infinite cycles in transformAfter.

if symbol is defining starting from this phase
current.validFor.firstPhaseId < phase.id is always true.
If additionally f changes the initial symbol,
(current ne symbol.current) will always be true.

Else if a symbol has a single denotation that spawns all periods,
which is changed, second cycle becomes infinite.

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