RFR 8171981: JShell: Fails compilation: new Object().getClass().getSuperclass()

[Robert Field]

Please review....

Bug:

     https://bugs.openjdk.java.net/browse/JDK-8171981

Webrev:

     http://cr.openjdk.java.net/~rfield/8171981v0.webrev/

Notes:

There were two different mechanisms for determining type: one used in 
evaluation and one available in the API.  Both had 
limitations/problems.  Both used TypePrinter which was the cause of the 
reported problem.

I've unified handling, discarded both old approaches, using a visitor 
instead.
I've separated var type name determination (used in code generation -- 
no type variables) from other type printing (used in docs).
Adopted Maurizo's handling of captured types.
Added debugging support for wraps.
Added lots more tests, including tests inspired by JEP-286.  All new 
tests, test both entry-points.
Thanks Maurizio and Dan!