Remove the comment on NumCPUs().

Change-Id: I6cdba5e3617e9c7a4b181d01b8b503c32a3ecf81
Reviewed-on: https://code-review.googlesource.com/c/re2/+/46699
Reviewed-by: Paul Wankadia <junyer@google.com>
diff --git a/re2/testing/regexp_benchmark.cc b/re2/testing/regexp_benchmark.cc
index 5e0e8a3..1fcc550 100644
--- a/re2/testing/regexp_benchmark.cc
+++ b/re2/testing/regexp_benchmark.cc
@@ -107,7 +107,6 @@
 }
 
 int NumCPUs() {
-  // Pretend to support multi-threaded benchmarking.
   return static_cast<int>(std::thread::hardware_concurrency());
 }