perf report: Refactor the branch info printing code

perf report: Refactor the branch info printing code

The branch info such as predicted/cycles/... are printed at the
callchain entries.

For example: perf report --branch-history --no-children --stdio

    --1.07%--main div.c:39 (predicted:52.4% cycles:1 iterations:17)
              main div.c:44 (predicted:52.4% cycles:1)
              main div.c:42 (cycles:2)
              compute_flag div.c:28 (cycles:2)
              compute_flag div.c:27 (cycles:1)
              rand rand.c:28 (cycles:1)
              rand rand.c:28 (cycles:1)
              __random random.c:298 (cycles:1)
              __random random.c:297 (cycles:1)
              __random random.c:295 (cycles:1)
              __random random.c:295 (cycles:1)
              __random random.c:295 (cycles:1)

But the current code is difficult to maintain and extend. This patch
refactors the code for easy maintenance.

Change log:

v6: 1. Put the multiline condition code into {} brackets in
       counts_str_build()

    2. Keep the original display order, that is:
       predicted, abort, cycles, iterations

v5: It's a new patch in v5 patch series.

Signed-off-by: Yao Jin <yao.jin@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1500379995-6449-5-git-send-email-yao.jin@linux.intel.com
[ Don't use 'index' as a name for a variable, it shadows a globa decl in older distros ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>