perf tests stat+json_output: Include sanity check for topology

perf tests stat+json_output: Include sanity check for topology

Testcase stat+json_output.sh fails in powerpc:

	86: perf stat JSON output linter : FAILED!

The testcase "stat+json_output.sh" verifies perf stat JSON output. The
test covers aggregation modes like per-socket, per-core, per-die, -A
(no_aggr mode) along with few other tests. It counts expected fields for
various commands. For example say -A (i.e, AGGR_NONE mode), expects 7
fields in the output having "CPU" as first field. Same way, for
per-socket, it expects the first field in result to point to socket id.
The testcases compares the result with expected count.

The values for socket, die, core and cpu are fetched from topology
directory:

  /sys/devices/system/cpu/cpu*/topology.

For example, socket value is fetched from "physical_package_id" file of
topology directory.  (cpu__get_topology_int() in util/cpumap.c)

If a platform fails to fetch the topology information, values will be
set to -1. For example, incase of pSeries platform of powerpc, value for
"physical_package_id" is restricted and not exposed. So, -1 will be
assigned.

Perf code has a checks for valid cpu id in "aggr_printout"
(stat-display.c), which displays the fields. So, in cases where topology
values not exposed, first field of the output displaying will be empty.
This cause the testcase to fail, as it counts  number of fields in the
output.

Incase of -A (AGGR_NONE mode,), testcase expects 7 fields in the output,
becos of -1 value obtained from topology files for some, only 6 fields
are printed. Hence a testcase failure reported due to mismatch in number
of fields in the output.

Patch here adds a sanity check in the testcase for topology.  Check will
help to skip the test if -1 value found.

Fixes: 0c343af2a2f82844 ("perf test: JSON format checking")
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Suggested-by: Ian Rogers <irogers@google.com>
Suggested-by: James Clark <james.clark@arm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Cc: Claire Jensen <cjense@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Link: https://lore.kernel.org/r/20221006155149.67205-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>