perf report: Fix and improve the displaying of per-thread event counters

perf report: Fix and improve the displaying of per-thread event counters

Improve and fix the handling of per-thread counter stats
recorded via perf record -s. Previously we only displayed
it in debug printouts (-D) and even that output was hard
to disambiguate.

I moved everything to utils/values.[ch] so that we may reuse
it in perf stat.

We get something like this now:

 #  PID   TID  cache-misses  cache-references
   4658  4659        495581           3238779
   4658  4662        498246           3236823
   4658  4663        499531           3243162

Then it'll be easy to add --pretty=raw to display a single line per thread/event.

By the way, -S was also used for --symbol... So I used -T/--thread here.

perf report: Add -T/--threads to display per-thread counter values

 We get something like this now:
 #  PID   TID  cache-misses  cache-references
   4658  4659        495581           3238779
   4658  4662        498246           3236823
   4658  4663        499531           3243162

Per-thread arrays of counter values are managed in utils/values.[ch]

Signed-off-by: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>