Issue #1555: Decrease visibility of public constructor in non-public class

Fixes `PublicConstructorInNonPublicClass` inspection violations.

Description:
>Reports all constructors in non-public classes that are declared public.

src/it/java/com/google/checkstyle/test/base/BaseCheckTestSupport.java

@@ -34,7 +34,7 @@ public abstract class BaseCheckTestSupport
     static class BriefLogger
         extends DefaultLogger
     {
-        public BriefLogger(OutputStream out) throws UnsupportedEncodingException
+        BriefLogger(OutputStream out) throws UnsupportedEncodingException
         {
             super(out, true);
         }