perf report: Fix --task and --stat with pipe input

Current 'perf report' fails to process a pipe input when --task or
--stat options are used. This is because they reset all the tool
callbacks and fails to find a matching event for a sample.

When pipe input is used, the event info is passed via ATTR records so it
needs to handle that operation. Otherwise the following error occurs.
Note, -14 (= -EFAULT) comes from evlist__parse_sample():

# perf record -a -o- sleep 1 | perf report -i- --stat
Can't parse sample, err = -14
0x271044 [0x38]: failed to process type: 9
Error:
failed to process sample
#

Committer testing:

Before:

$ perf record -o- sleep 1 | perf report -i- --stat
Can't parse sample, err = -14
[ perf record: Woken up 1 times to write data ]
0x1350 [0x30]: failed to process type: 9
Error:
failed to process sample
[ perf record: Captured and wrote 0.000 MB - ]
$

After:

$ perf record -o- sleep 1 | perf report -i- --stat
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.000 MB - ]

Aggregated stats:
TOTAL events: 41
COMM events: 2 ( 4.9%)
EXIT events: 1 ( 2.4%)
SAMPLE events: 9 (22.0%)
MMAP2 events: 4 ( 9.8%)
ATTR events: 1 ( 2.4%)
FINISHED_ROUND events: 1 ( 2.4%)
THREAD_MAP events: 1 ( 2.4%)
CPU_MAP events: 1 ( 2.4%)
EVENT_UPDATE events: 1 ( 2.4%)
TIME_CONV events: 1 ( 2.4%)
FEATURE events: 19 (46.3%)
cycles:uhH stats:
SAMPLE events: 9
$

Fixes: a4a4d0a7a2b20f78 ("perf report: Add --stats option to display quick data statistics")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210630043058.1131295-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>