Add inspection: Refactor sealed sub-class to object #KT-20305 Fixed

idea/testData/multiFileLocalInspections/convertSealedSubClassToObject/convertInOtherFiles/before/JavaSealedTest.java

@@ -0,0 +1,14 @@
+import seal.*
+
+class JavaSealedTest {
+    Sealed sealedInsideClass = new SubSealed();
+
+    public void testSeal() {
+        Sealed sealedInsideMethod = new SubSealed();
+
+        new SubSealed().toString();
+
+        // Will be deleted because Java doesn't allow a expression to be used as a statement
+        new SubSealed();
+    }
+}

idea/testData/multiFileLocalInspections/convertSealedSubClassToObject/convertInOtherFiles/before/KotlinSealedTest.kt

@@ -0,0 +1,13 @@
+import seal.*
+
+val sealedOutsideClass = SubSealed()
+
+class KotlinSealedTest {
+    val sealedInsideClass = SubSealed()
+
+    fun testSeal() {
+        val sealedInsideMethod = SubSealed()
+
+        SubSealed()
+    }
+}

idea/testData/multiFileLocalInspections/convertSealedSubClassToObject/convertInOtherFiles/before/Seal.kt

@@ -0,0 +1,5 @@
+package seal
+
+sealed class Sealed
+
+<caret>class SubSealed : Sealed()