perf annotate: Prefer passing evsel to evsel->core.idx

perf annotate: Prefer passing evsel to evsel->core.idx

An evsel idx may not be stable due to sorting, evlist removal,
etc. Try to reduce it being part of APIs by explicitly passing the
evsel in annotate code. Internally the code just reads evsel->core.idx
so behavior is unchanged.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Chen Ni <nichen@iscas.ac.cn>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Link: https://lore.kernel.org/r/20250117181848.690474-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>