Convert "lift return / assignment" intentions into a single inspection

Also includes minor test fix, related to KT-14900

idea/testData/inspectionsLocal/liftOut/whenToAssignment/insideLoop.kt.after

@@ -0,0 +1,13 @@
+fun foo(): Int {
+    var res = 0
+    loop@ while (true) {
+        res += when (1) {
+            1 -> 1
+            2 -> throw Exception()
+            3 -> break@loop
+            4 -> continue@loop
+            else -> return -1
+        }
+    }
+    return res
+}