Select operations in erasure should fix symbols in types.
Select operations in erasure should fix symbols in types.

Otherwise we get binding races, e.g. for pos/t2133.scala after mixin
because we create same-named symbols in subclasses, and type refs now
can refer to the subclass symbol where previously they refereed to the
superclass symbol. To avoid a data race the new term ref will have a
fixed symbol.

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