Fix forbidden API violations in benchmark classes

Use Locale.ROOT in printf calls to avoid forbidden default locale usage

Author: salvatorecampagna

lucene/benchmark-jmh/src/java/org/apache/lucene/benchmark/jmh/LiveDocsBenchmark.java

@@ -198,6 +198,7 @@ public void setup() {
     long denseBytes = denseLiveDocs.ramBytesUsed();
     double overheadPct = ((double) sparseBytes / denseBytes - 1.0) * 100;
     System.out.printf(
+        java.util.Locale.ROOT,
         "[Memory] pattern=%s, maxDoc=%,d, delRate=%.1f%%, deleted=%,d: Sparse=%,d bytes, Dense=%,d bytes, Overhead=%.1f%%%n",
         deletionPattern,
         maxDoc,

lucene/benchmark-jmh/src/java/org/apache/lucene/benchmark/jmh/LiveDocsPathologicalBenchmark.java

@@ -170,6 +170,7 @@ public void setup() {
 
     double overheadPct = ((double) sparseBytes / denseBytes - 1.0) * 100;
     System.out.printf(
+        java.util.Locale.ROOT,
         "[Memory] maxDoc=%,d, deletionRate=%.4f%%, deleted=%,d: Sparse=%,d bytes, Dense=%,d bytes, Overhead=%.1f%%%n",
         maxDoc, deletionRate * 100, deletedCount, sparseBytes, denseBytes, overheadPct);
   }