perf stat: Do not align time prefix in CSV output

We don't care about the alignment in the CSV output as it's intended for machine
processing.  Let's get rid of it to make the output more compact.

Before:

  # perf stat -a --summary -I 1 -x, true
       0.001149309,219.20,msec,cpu-clock,219322251,100.00,219.200,CPUs utilized
       0.001149309,144,,context-switches,219241902,100.00,656.935,/sec
       0.001149309,38,,cpu-migrations,219173705,100.00,173.358,/sec
       0.001149309,61,,page-faults,219093635,100.00,278.285,/sec
       0.001149309,10679310,,cycles,218746228,100.00,0.049,GHz
       0.001149309,6288296,,instructions,218589869,100.00,0.59,insn per cycle
       0.001149309,1386904,,branches,218428851,100.00,6.327,M/sec
       0.001149309,56863,,branch-misses,218219951,100.00,4.10,of all branches
           summary,219.20,msec,cpu-clock,219322251,100.00,20.025,CPUs utilized
           summary,144,,context-switches,219241902,100.00,656.935,/sec
           summary,38,,cpu-migrations,219173705,100.00,173.358,/sec
           summary,61,,page-faults,219093635,100.00,278.285,/sec
           summary,10679310,,cycles,218746228,100.00,0.049,GHz
           summary,6288296,,instructions,218589869,100.00,0.59,insn per cycle
           summary,1386904,,branches,218428851,100.00,6.327,M/sec
           summary,56863,,branch-misses,218219951,100.00,4.10,of all branches

After:

  0.001148449,224.75,msec,cpu-clock,224870589,100.00,224.747,CPUs utilized
  0.001148449,176,,context-switches,224775564,100.00,783.103,/sec
  0.001148449,38,,cpu-migrations,224707428,100.00,169.079,/sec
  0.001148449,61,,page-faults,224629326,100.00,271.416,/sec
  0.001148449,12172071,,cycles,224266368,100.00,0.054,GHz
  0.001148449,6901907,,instructions,224108764,100.00,0.57,insn per cycle
  0.001148449,1515655,,branches,223946693,100.00,6.744,M/sec
  0.001148449,70027,,branch-misses,223735385,100.00,4.62,of all branches
  summary,224.75,msec,cpu-clock,224870589,100.00,21.066,CPUs utilized
  summary,176,,context-switches,224775564,100.00,783.103,/sec
  summary,38,,cpu-migrations,224707428,100.00,169.079,/sec
  summary,61,,page-faults,224629326,100.00,271.416,/sec
  summary,12172071,,cycles,224266368,100.00,0.054,GHz
  summary,6901907,,instructions,224108764,100.00,0.57,insn per cycle
  summary,1515655,,branches,223946693,100.00,6.744,M/sec
  summary,70027,,branch-misses,223735385,100.00,4.62,of all branches

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20221123180208.2068936-4-namhyung@kernel.org


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