Large int/log values are truncated in locals display

[GoogleCodeExporter]

What steps will reproduce the problem?
1.  Create a program that creates a long or int variable whose value cannot
be stored in 24 or 28 bits.  (Actual value depends on how emacs was built)
2.  Break in jdibug where the variable is visible.

What is the expected output? What do you see instead?
The high order bits are dropped.  Integer.MIN_VALUE displays as -1 and
Integer.MAX_VALUE displays as 0.

Please use labels and text to provide additional information.

The current display converts the bytes to a number using emacs integers,
which only have 24-28 bits.  (I think the exact value depends on how emacs
was built.)  To fix this, we need to write something that builds up the
string from the bytes without going through an intermediate number.

Original issue reported on code.google.com by udalrich.schermer on 27 Mar 2010 at 9:23