perf session: Cleanup trace_event

perf session: Cleanup trace_event

ASan reports several memory leaks when running:

  # perf test "82: Use vfs_getname probe to get syscall args filenames"

many of which are related to session->tevent.

This patch will solve this problem, then next patch will fix the
remaining memory leaks in 'perf script'.

This bug is due to a missing deallocation of the trace_event data
strutures.

This patch adds the missing trace_event__cleanup() in
perf_session__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/fa2a3f221d90e47ce4e5b7e2d6e64c3509ddc96a.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>