perf stat: Add --per-node agregation support

Adding new --per-node option to aggregate counts per NUMA
nodes for system-wide mode measurements.

You can specify --per-node in live mode:

  # perf stat  -a -I 1000 -e cycles --per-node
  #           time node   cpus             counts unit events
       1.000542550 N0       20          6,202,097      cycles
       1.000542550 N1       20            639,559      cycles
       2.002040063 N0       20          7,412,495      cycles
       2.002040063 N1       20          2,185,577      cycles
       3.003451699 N0       20          6,508,917      cycles
       3.003451699 N1       20            765,607      cycles
  ...

Or in the record/report stat session:

  # perf stat record -a -I 1000 -e cycles
  #           time             counts unit events
       1.000536937         10,008,468      cycles
       2.002090152          9,578,539      cycles
       3.003625233          7,647,869      cycles
       4.005135036          7,032,086      cycles
  ^C     4.340902364          3,923,893      cycles

  # perf stat report --per-node
  #           time node   cpus             counts unit events
       1.000536937 N0       20          9,355,086      cycles
       1.000536937 N1       20            653,382      cycles
       2.002090152 N0       20          7,712,838      cycles
       2.002090152 N1       20          1,865,701      cycles
       3.003625233 N0       20          6,604,441      cycles
       3.003625233 N1       20          1,043,428      cycles
       4.005135036 N0       20          6,350,522      cycles
       4.005135036 N1       20            681,564      cycles
       4.340902364 N0       20          3,403,188      cycles
       4.340902364 N1       20            520,705      cycles

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20190904073415.723-4-jolsa@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>