perf trace: Rename delivery functions to ease making ordered_events selectable

Just hide a bit more how events gets delivered, hiding ordered_events
details from the main loop.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-lxwwf3238ta4neq2zh1y1h45@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>