Cache AnnotatedTypes
Cache AnnotatedTypes

This leads to an increase of cachable applied types. For typer/*.scala:

   cached applied types      uncached applied types
now   32.3K                    0.4K
was   30k                     12.4K

# Conflicts:
#	compiler/src/dotty/tools/dotc/core/Types.scala

dotty-staging/dotty,sjrd/dotty,dotty-staging/dotty,sjrd/dotty,sjrd/dotty,lampepfl/dotty,dotty-staging/dotty,lampepfl/dotty,dotty-staging/dotty,sjrd/dotty,lampepfl/dotty,sjrd/dotty,lampepfl/dotty,lampepfl/dotty,dotty-staging/dotty