perf trace: Free syscall tp fields in evsel->priv

perf trace: Free syscall tp fields in evsel->priv

ASan reports several memory leaks running:

  # perf test "88: Check open filename arg using perf trace + vfs_getname"

The third of these leaks is related to evsel->priv fields of sycalls
never being deallocated.

This patch adds the function evlist__free_syscall_tp_fields which
iterates over all evsels in evlist, matching syscalls, and calling the
missing frees.

This new function is called at the end of trace__run, right before
calling evlist__delete.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/46526611904ec5ff2768b59014e3afce8e0197d1.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>