Corrected behavior of Constructor.newInstance on abstract classes.

The VM now throws an exception when somebody tries to create an instance
of an abstract class through a Constructor object.  It also ensures that
the class is initialized before attempting to create an instance.

This change adds some Constructor tests to the 042-new-instance VM test.
(It also pulls in some additions that were made to the 042 test back
in March, on the p4 master branch.)
6 files changed