-Dp does work on EBCDIC.
toke.c: Generalize trace for non-ASCII platform

This was very ASCII-specific.  The newer is clearer and saves a test.
perly.c: Fix EBCDIC bug

The code was changing the value in a structure on EBCDIC platforms.  It
turns out that that structure element is used later under quite limited
circumstances.  The changed value is actually only needed during an
array look-up, so we no longer store the change.