perf stat: Make options local

Reduce the scope of stat_options to cmd_stat, and pass as an argument
to __cmd_record. This is done to make more localized changes to the
options in later patches. A side-effect of the change is to reduce the
size of a stripped PIE perf binary by 5952 bytes. The savings come
mainly in the dynamic relocation section.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240605063828.195700-1-irogers@google.com