Moves AbstractFileClassLoader to scala-reflect.jar

Its string name was used in ReflectionUtils and became broken after repl
got factored out. This hints that that classloader belongs to where it is
used, i.e. to scala-reflect.jar.

Moreover AbstractFile is defined in scala-reflect.jar, so it's only
logical to also define a derived classloader in scala-reflect.jar.
SI-7436 Varargs awareness for super param aliasing.

Don't consider a super class parameter accessor to be
an alias if it is a repeated. Parameter aliases are used
to avoid retaining redundant fields in the subclass; but
that optimization is out of the question here.
Merge pull request #2568 from scalamacros/topic/abstractfile-classloader

Moves AbstractFileClassLoader to scala-reflect.jar
SI-6811 Deprecate scala.util.parsing.json
Merge pull request #2576 from retronym/ticket/7436

SI-7436 Varargs awareness for super param aliasing.
Merge pull request #2581 from soc/SI-6811-json

SI-6811 Deprecate scala.util.parsing.json