Signed-off-by: Xiaoxi Chen <xiaoxchen@ebay.com>

Ports the consumer-side timer change from stable/v7.x forward to v8. Upstream
ef9ab9d upgrades the 8 recurring timer callbacks (cp_mgr, resource_mgr,
log_dev, raft_repl_service) from void(void*) to void(void*, uint64_t exp_count),
logging once when the timerfd fell behind (exp_count > 1) instead of letting
the callback fire N times -- the consumer half of iomgr's SDSTOR-22330.

Resolution notes (the literal patch did not apply cleanly):
- conanfile.py: kept v8.x (homestore 8.0.0, iomgr/[^13.0]@oss/dev, sisl 14.5,
  nuraft_mesg 5.0); dropped upstream's 7.5.10 / iomgr 12.0.3 bumps -- v8 is
  already on iomgr 13, whose backward-compat overloads make this an enhancement
  rather than a compile fix.
- cp_mgr cp-timer: kept v8's coroutine body detail::detach(trigger_cp_flush(false))
  and added the exp_count guard/log around it.
- The other 7 callbacks took the upstream form (bodies were unchanged in v8).
- .github/workflows/merge_build.yml: kept v8.x's reworked workflow; the
  unrelated ChainBuild commit (55ed28e) is intentionally not adopted.