Java to Kotlin converter: minor refactoring of switch conversion + no need for empty else

j2k/tests/testData/ast/switch/emptySwitch.kt

@@ -5,8 +5,7 @@ public class NonDefault {
             val value = 3
             val valueString = ""
             when (value) {
-                else -> {
-                }
+
             }
             System.out.println(valueString)
         }

j2k/tests/testData/ast/switch/nondefault.kt

@@ -14,8 +14,6 @@ public class NonDefault {
                 3 -> {
                     valueString = "THREE"
                 }
-                else -> {
-                }
             }
             System.out.println(valueString)
         }