leaking_addresses: Always print a trailing newline

leaking_addresses: Always print a trailing newline

For files that lack trailing newlines and match a leaking address (e.g.
wchan[1]), the leaking_addresses.pl report would run together with the
next line, making things look corrupted.

Unconditionally remove the newline on input, and write it back out on
output.

[1] https://lore.kernel.org/all/20210103142726.GC30643@xsang-OptiPlex-9020/

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211008111626.151570317@infradead.org