perf stat: Print per-thread shadow stats

The function perf_stat__print_shadow_stats() is called to print the
shadow stats on a set of static variables.

But the static variables are the limitations to support
per-thread shadow stats.

This patch lets the perf_stat__print_shadow_stats() support
to print the shadow stats from a input parameter 'st'.

It will not directly get value from static variable. Instead,
it now uses runtime_stat_avg() and runtime_stat_n() to get and
compute the values.

Signed-off-by: Jin Yao <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: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1512482591-4646-6-git-send-email-yao.jin@linux.intel.com


[ Rename 'stat' variables to 'st' to build on centos:{5,6} and others where it shadows a global declaration ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>