[m-rev.] for review: delete references to Erlang in the compiler

[Zoltan Somogyi]

The only nontrivial part of this is arranging short-term backwards compatibility
in item_type_repn_infos, and since I am the expert on that, I thought I can do this
more easily than Peter. Of course, this diff won't bootcheck until all Erlang foreign
code is deleted from the system, which is a diff that Peter hasn't committed yet.
Even after that, I intend to wait at least a day before committing this.

For review by Peter.

Zoltan.
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