Problem

Unused benches, workgen runners, and the C example for tiered storage are still in tree. They must go before src/tiered is deleted. This ticket is only those dead trees. It does not edit live csuite, format, Catch2, or test/utility.

Change

Delete:

• examples/c/ex_tiered.c and its CMake target
• bench/tiered/ (push_pull.c and CMakeLists) and the root add_subdirectory
• bench/workgen/runner/microbenchmark_tiered_*.py
• bench/wtperf/runners/tiered-btree.wtperf and tiered-read-only.wtperf

Optional: fix stale flush_tier comments in microbenchmark_rts_*.py.

Do not touch timestamp_abort, schema_abort, random_directio, test/checkpoint, test/format, Catch2, test/utility, parse_opts, or wtperf.c internals. Do not change src/. Smallest hunks; do not move unrelated functions.

Test

Ninja build. Confirm the deleted targets are gone from the build. No abort-test or format behavior change.