perf tests task_analyzer: Skip tests if no libtraceevent support

perf tests task_analyzer: Skip tests if no libtraceevent support

Test "perf script task-analyzer tests" fails in environment with missing
libtraceevent support, as perf record fails to create the perf.data
file, which further tests depend on.

Instead, when perf is not compiled with libtraceevent support, skip
those tests instead of failing them, by checking the output of `perf
record --dry-run` to see if it prints the error "libtraceevent is
necessary for tracepoint support"

For the following output, perf compiled with: `make NO_LIBTRACEEVENT=1`

Before the patch:

108: perf script task-analyzer tests                                 :
test child forked, pid 24105
failed to open perf.data: No such file or directory  (try 'perf record' first)
FAIL: "invokation of perf script report task-analyzer command failed" Error message: ""
FAIL: "test_basic" Error message: "Failed to find required string:'Comm'."
failed to open perf.data: No such file or directory  (try 'perf record' first)
FAIL: "invokation of perf script report task-analyzer --ns --rename-comms-by-tids 0:random command failed" Error message: ""
FAIL: "test_ns_rename" Error message: "Failed to find required string:'Comm'."
failed to open perf.data: No such file or directory  (try 'perf record' first)
<...>
perf script task-analyzer tests: FAILED!

With this patch, the script instead returns 2 signifying SKIP, and after
the patch:

108: perf script task-analyzer tests                                 :
test child forked, pid 26010
libtraceevent is necessary for tracepoint support
WARN: Skipping tests. No libtraceevent support
test child finished with -2
perf script task-analyzer tests: Skip

Fixes: e8478b84d6ba9ccf ("perf test: Add new task-analyzer tests")
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Petar Gligoric <petar.gligoric@rohde-schwarz.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230613164145.50488-18-atrajeev@linux.vnet.ibm.com
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>