refactor: simplify buildProjectedQuery using String.join

Author: nikagra

driver-core/src/main/java/com/datastax/driver/core/ControlConnection.java

@@ -963,16 +963,8 @@ static Set<String> intersectWithNeeded(ResultSet rs, ImmutableSet<String> needed
    */
   @VisibleForTesting
   static String buildProjectedQuery(String table, Set<String> columns, String whereClause) {
-    StringBuilder sb = new StringBuilder("SELECT ");
-    boolean first = true;
-    for (String col : columns) {
-      if (!first) sb.append(", ");
-      sb.append(col);
-      first = false;
-    }
-    sb.append(" FROM ").append(table);
-    if (whereClause != null) sb.append(" WHERE ").append(whereClause);
-    return sb.toString();
+    String query = "SELECT " + String.join(", ", columns) + " FROM " + table;
+    return whereClause != null ? query + " WHERE " + whereClause : query;
   }
 
   private void refreshNodeListAndTokenMap(