perf auxtrace: Pass perf_env from session through to mmap read

 auxtrace_mmap__read and auxtrace_mmap__read_snapshot end up calling
 `evsel__env(NULL)` which returns the global perf_env variable for the
 host. Their only call is in perf record. Rather than use the global
 variable pass through the perf_env for `perf record`.

Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250724163302.596743-18-irogers@google.com


Signed-off-by: Namhyung Kim <namhyung@kernel.org>