perf stat: Fix metrics calculation with event qualifiers

Currently in perf IPC and other metrics cannot be directly shown
separately for both user and kernel in a single run. The problem was
that the metrics matching code did not check event qualifiers.

With this patch the following case works correctly.

% perf stat -e cycles:k,cycles:u,instructions:k,instructions:u true

 Performance counter stats for 'true':

           531,718      cycles:k
           203,895      cycles:u
           338,151      instructions:k            #    0.64  insns per cycle
           105,961      instructions:u            #    0.52  insns per cycle

       0.002989739 seconds time elapsed

Previously it would misreport the ratios because they were matching the
wrong value.

The patch is fairly big, but quite mechanic as it just adds context
indexes everywhere.
Reported-by: William Cohen <wcohen@redhat.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: William Cohen <wcohen@redhat.com>
Link: http://lkml.kernel.org/r/1428441919-23099-3-git-send-email-jolsa@kernel.orgSigned-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>