trace2: add dots directly to strbuf in perf_fmt_prepare()
The initialization function of the Trace2 performance format target sets
aside a stash of dots for indenting output. Get rid of it and use
strbuf_addchars() to provide dots on demand instead. This shortens the
code, gets rid of a small heap allocation and is a bit more efficient.
Signed-off-by: René Scharfe <l.s.r@web.de>
Acked-by: Jeff King <peff@peff.net>
Acked-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>