Exclude .kt files from serializable inner class query

Author: tamasvajk

java/ql/src/Likely Bugs/Serialization/NonSerializableInnerClass.ql

@@ -77,7 +77,7 @@ predicate exceptions(NestedClass inner) {
 
 from NestedClass inner, Class outer, string advice
 where
-  inner.fromSource() and
+  inner.getFile().isJavaSourceFile() and
   isSerializable(inner) and
   outer = enclosingInstanceType+(inner) and
   not isSerializable(outer) and

java/ql/test/kotlin/query-tests/NonSerializableInnerClass/NonSerializableInnerClass.expected

@@ -1,2 +0,0 @@
-| NonSerializableInnerClassTest.kt:4:3:5:3 | X | Serializable inner class of non-serializable class $@. Consider making the class static or implementing readObject() and writeObject(). | NonSerializableInnerClassTest.kt:3:1:6:1 | A | A |
-| NonSerializableInnerClassTest.kt:9:3:10:3 | X | Serializable inner class of non-serializable class $@. Consider making the class static or implementing readObject() and writeObject(). | NonSerializableInnerClassTest.kt:8:1:11:1 | B | B |