perf tests: Call test_attr__open() directly

perf tests: Call test_attr__open() directly

There's no longer need to call test_attr__open() from
sys_perf_event_open(), because both 'perf record' and 'perf stat' call
evsel__open_cpu(), so we can call it directly from there and not polute
the perf-sys.h header.

Committer testing:

Before and after:

  # perf test attr
  17: Setup struct perf_event_attr                                    : Ok
  49: Synthesize attr update                                          : Ok
  # perf test -v attr
  17: Setup struct perf_event_attr                                    :
  --- start ---
  test child forked, pid 2170868
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-any_ret'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-any_ret'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-C0'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-graph-fp'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-period'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-group-sampling'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-freq'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-detailed-3'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-k'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-k'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-group1'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-u'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-u'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-basic'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-any_call'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-any_call'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-default'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-graph-dwarf'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-no-buffering'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-raw'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-detailed-2'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-count'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-data'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-any'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-any'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-group'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-any'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-any'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-graph-default'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-no-samples'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-C0'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-no-inherit'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-ind_call'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-ind_call'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-basic'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-group1'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-pfm-period'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-pfm-period'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-detailed-1'
  running '/home/acme/libexec/perf-core/tests/attr/test-stat-no-inherit'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-hv'
  unsupp  '/home/acme/libexec/perf-core/tests/attr/test-record-branch-filter-hv'
  running '/home/acme/libexec/perf-core/tests/attr/test-record-group'
  test child finished with 0
  ---- end ----
  Setup struct perf_event_attr: Ok
  49: Synthesize attr update                                          :
  --- start ---
  test child forked, pid 2171004
  test child finished with 0
  ---- end ----
  Synthesize attr update: Ok
  #

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200827193201.GB127372@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>