remove redundant public modifier

Author: Vladimir Kotal

opengrok-indexer/src/test/java/org/opengrok/indexer/analysis/PlainAnalyzerTest.java

@@ -69,7 +69,7 @@ void testXrefTimeout() {
     private static class TestablePlainAnalyzer extends PlainAnalyzer {
         boolean writeXrefCalled;
 
-        public TestablePlainAnalyzer() {
+        TestablePlainAnalyzer() {
             super(PlainAnalyzerFactory.DEFAULT_INSTANCE);
         }