Lift assignment out: do not report when assignment variables are different

#KT-38649 Fixed

idea/testData/inspectionsLocal/liftOut/whenToAssignment/differentVariablesWithSame.kt

@@ -0,0 +1,18 @@
+// PROBLEM: none
+// WITH_RUNTIME
+
+class A {
+    val list: MutableList<String> = mutableListOf()
+}
+
+class B {
+    val list: MutableList<String> = mutableListOf()
+}
+
+fun Any.add(s: String) {
+    <caret>when (this) {
+        is A -> list += s
+        is B -> list += s
+        else -> throw IllegalStateException()
+    }
+}