fix warning

Author: breedx-splk

sdk/metrics/src/jmh/java/io/opentelemetry/sdk/metrics/internal/aggregator/HistogramValueGenerator.java

@@ -49,7 +49,7 @@ private static class PoolSupplier implements DoubleSupplier {
     private final double[] pool;
     private final AtomicInteger idx = new AtomicInteger(0);
 
-    public PoolSupplier(double[] pool) {
+    private PoolSupplier(double[] pool) {
       this.pool = pool;
     }