Update a comment in CacheLocalityBenchmark.cpp

Summary: [Folly] Update a comment in `CacheLocalityBenchmark.cpp` to refer to the direct function used for fetching the thread-id.

Reviewed By: Orvid

Differential Revision: D19226855

fbshipit-source-id: 8cf203daa7b3fbc00e387dca881be7f9ce47af95

folly/concurrency/test/CacheLocalityBenchmark.cpp

@@ -105,7 +105,7 @@ BENCHMARK(CachedAccessSpreaderAtomicIncrement, iters) {
 // Getcpu refers to the vdso getcpu implementation.  ThreadLocal refers
 // to execution using SequentialThreadId, the fallback if the vdso
 // getcpu isn't available.  PthreadSelf hashes the value returned from
-// pthread_self() as a fallback-fallback for systems that don't have
+// getCurrentThreadID() as a fallback-fallback for systems that don't have
 // thread-local support.
 //
 // At 16_stripe_0_work and 32_stripe_0_work there is only L1 traffic,