Fix futex_benchmark.

- Fix definitions of Futex* wrappers.

- Correctly handle glibc syscall() (which returns -1 and sets errno instead of
  returning the raw syscall return value).

- De-parameterize FutexWaitBitset, which was apparently intended to test with
  deadlines of between 0 and 100000 nanoseconds after the Unix epoch, but was
  broken due to the preceding two issues.

- Use wall time to measure the durations of tests that are expected to block
  (and thus stop accumulating CPU time).

- Require 5s for all tests to improve robustness in the presence of sentry GC.

- Remove FutexContend and FutexContendDeadline; it's unclear what these are
  supposed to measure, given that (1) FutexLock is unrealistically inefficient
  and (2) the benchmark rewards slow scheduling (since this reduces
  contention).

PiperOrigin-RevId: 302925246

0 files changed, 0 insertions, 0 deletions