When trap() causes a panic, have stacktrace() use ddb to find the symbol names if option DDB, instead of the fn_name() helper which only knows about trap() anyway.
When trap() causes a panic, have stacktrace() use ddb to find the symbol
names if option DDB, instead of the fn_name() helper which only knows about
trap() anyway.

While there, do not attempt to print the function arguments after the first
frame, since they are known to be clobbered.

orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars,orumin/openbsd-efivars