perf test event_update: Fix memory leak of evlist

ASan reports a memory leak when running:

  # perf test "49: Synthesize attr update"

Caused by evlist not being deleted.

This patch adds the missing evlist__delete and removes the
perf_cpu_map__put since it's already being deleted by evlist__delete.

Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
Fixes: a6e52817

 ("perf tools: Add event_update event unit type")
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/f7994ad63d248f7645f901132d208fadf9f2b7e4.1626343282.git.rickyman7@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>