…n they shouldn't be.

…harmap.

…ngs in EncodingManager.

A side effect of this change is we're no longer updating the JRuby runtime's default_external and default_internal values. As a result, we can't use methods from the JRuby runtime that rely on those values being up-to-date. Since RubyString#inspect is one such method, we have to move that back out to Ruby (String#inspect). This code has ping-ponged a few times between a Ruby and Java implementation. It appears whatever issue forced the move back to Java (i.e., RubyString#inspect) has been addressed.

…codings.

Also, started moving non-standard Encoding methods out to Truffle::Encoding.

These methods became a lot simpler once we started tracking default_external and default_internal encodings in the EncodingManager.

…haring.

…e during initialization.

This reverts a large part of 1f88220 and 3beeeb8. As it turns out, the iterators provided by jcodings are a good enough interface and other usability improvements have been made, obviating the need for this visitor pattern.

We load all encodings eagerly and account for dummy encodings during bootstrap.

The file on Travis refers to snapshot servers that are no longer online and may cause build problems.