Merge branch 'selftests-bpf-xdp-lb-benchmark-fixes'

Puranjay Mohan says:

====================
selftests/bpf: XDP LB benchmark fixes

Changelog:
v1: https://lore.kernel.org/all/20260519163632.2220753-1-puranjay@kernel.org/
Changes in v2:
- Drop patch 3 as it was fixing a situation that can never happen in practice.
- Replace | 1 logic in patch 1 with replacing ^ operator with +

Three bug fixes and one improvement for the XDP LB and batch-timing
benchmarks.

The cold_lru validation was failing a lot because batch_hash could
compute to zero when batch_gen matched the CPU id. Similarly,
pre-populated UDP LRU entries had atime=0 so they'd expire immediately
on any CPU that calibration didn't warm. Both are fixed in patches 1-2.

Patch 3 adds IQR outlier filtering to the timing stats to stabilize
scenarios with high stddev.
====================

Link: https://patch.msgid.link/20260520133338.3392667-1-puranjay@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>