ls: avoid redundant processing when already escaping

This is mainly noticeable when the multi-byte code
within ls.c is triggered by multi-byte quotes.

$ seq 200000 | xargs touch
$ time ls-old -U --quoting=locale --hide-control-chars >/dev/null
real    0m0.483s
$ time ls-new -U --quoting=locale --hide-control-chars >/dev/null
real    0m0.430s

* src/ls.c (quote_name): Avoid rescanning the output looking for
unprintable chars when we know the quoting mode already escapes them.
* tests/misc/ls-misc.pl: Add tests for all quoting modes, with and
without -q, to verify this assumption.

0 files changed, 0 insertions, 0 deletions