Your wish is granted (in 5.8.5):
in reply to Re^3: Neat Debugger tricks
in thread Neat Debugger tricks
rerun reloads the program and applies all commands you've executed in the debugger to (theoretically) get you back to the same point.
$ perl -de0
Loading DB routines from perl5db.pl version 1.28
Editor support available.
Enter h or `h h' for help, or `man perldebug' for more help.
DB<1> h rerun
rerun Rerun session to current position.
rerun n Rerun session to numbered command.
rerun -n Rerun session to number'th-to-last command.