[tamnd]

The nightly bench on tinyconfig only reported 6 of the 15 benchmarks and never got to the memcpy control, so it always said the host was too noisy. tinyconfig has no AF_UNIX, so socketpair failed in unix-pingpong, fail() called exit(1) and nothing after it ran.

Now /bench forks a child for each benchmark. When a child fails it prints RK-BENCH-SKIP <name> and the next benchmark still runs. The Rust side already ignores lines that are not RK-BENCH <name> <ns>, and the console test now has a skip line in it. Plan 12.2 says the same thing.

Checked on server3 with the host gcc: all 15 lines as before, and with AF_UNIX swapped for a bad family the run prints RK-BENCH-SKIP unix-pingpong and still ends with memcpy. cargo test -p rk bench and clippy pass.

Part of #9.