Turn off Perl ornaments by default.

Also a small import fix for Perl.
Trampoline uninstallation fix (for perl).
Add fd passthrough test for Perl.
Perl-specific fixes for DMTCP invocation.
Only issue 'next n' commands with debugger support.
Several updates for Perl personality.

- Sanitize 'print' output correctly.
- Remove some unneeded methods that are implemented in the Personality
  superclass.
Fix race cond. capturing child output: for r-w.

There was a race that could affect reverse-watch. If the "evaluate_expression"
function was called while the child (debugger) was still printing output to the
screen, the saved value of the expression at the start of reverse-watch could
contain extraneous output from the child, or it could fail to capture the
expression value at all. This could cause reverse-watch to be unable to
determine an interval in which the expression changes value.
Add empty truth value <=> false for Perl.