Reduce time for optimize_test and use exactly one (unpinned) thread.

PiperOrigin-RevId: 691013413

Author: danielkeysers

backprop/optimize_test.cc

@@ -39,7 +39,7 @@
 namespace gcpp {
 
 TEST(OptimizeTest, GradientDescent) {
-  NestedPools pools(1);
+  NestedPools pools(1, /*pin=*/0, BoundedSlice(0, 1), BoundedSlice(0, 1));
   hwy::ThreadPool& pool = pools.Pool();
   std::mt19937 gen(42);
 

util/threading.h

@@ -361,7 +361,7 @@ class NestedPools {
   // only impose upper bounds on the number of detected packages and clusters
   // rather than defining the actual number of threads.
   //
-  // `pin` is 0 or 1 to force enable/disable, or -1 to choose automatically.
+  // `pin` is 0 or 1 to force disable/enable, or -1 to choose automatically.
   NestedPools(size_t max_threads, int pin = -1,
               BoundedSlice package_slice = BoundedSlice(),
               BoundedSlice cluster_slice = BoundedSlice(),