perf stat: Update per-thread shadow stats

The functions perf_stat__update_shadow_stats() is called to update the
shadow stats on a set of static variables.

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

This patch lets the perf_stat__update_shadow_stats() support to update
the shadow stats on a input parameter 'st' and uses
update_runtime_stat() to update the stats. It will not directly update
the static variables as before.

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/1512482591-4646-5-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>