bugfix: removing "y" and "n" from BooleanLiteralsHelper since there are test cases using "y" as valid column names.

Author: jgaleotti

client-java/sql/src/main/java/org/evomaster/client/java/sql/heuristic/BooleanLiteralsHelper.java

@@ -9,14 +9,14 @@
 public class BooleanLiteralsHelper {
 
     public static final Set<String> BOOLEAN_TRUE_LITERALS = new HashSet<>(
-            Arrays.asList("t", "true", "yes", "y", "on"));
+            Arrays.asList("t", "true", "yes", "on"));
 
     public static final Set<String> BOOLEAN_FALSE_LITERALS = new HashSet<>(
-            Arrays.asList("f", "false", "no", "n", "off"));
+            Arrays.asList("f", "false", "no", "off"));
 
     public static final Set<String> BOOLEAN_LITERALS =
             Stream.concat(Stream.concat(BOOLEAN_FALSE_LITERALS.stream(),
-                            BOOLEAN_TRUE_LITERALS.stream()),
+                                    BOOLEAN_TRUE_LITERALS.stream()),
                             Stream.of("unknown"))
                     .collect(Collectors.toSet());