Support cascade if / when in lift return / assignment intentions

So #KT-13458 Fixed
So #KT-13436 Fixed

idea/testData/intentions/branched/folding/ifToAssignment/cascadeIf.kt

@@ -0,0 +1,18 @@
+// WITH_RUNTIME
+fun test(x: Any) {
+    var res: String
+    <caret>if (x is String)
+        when {
+            x.length > 3 -> res = "long string"
+            else -> res = "short string"
+        }
+    else if (x is Int)
+        when {
+            x > 999 || x < -99 -> res = "long int"
+            else -> res = "short int"
+        }
+    else if (x is Long)
+        TODO()
+    else
+        res = "I don't know"
+}

idea/testData/intentions/branched/folding/ifToAssignment/cascadeIf.kt.after

@@ -0,0 +1,18 @@
+// WITH_RUNTIME
+fun test(x: Any) {
+    var res: String
+    <caret>res = if (x is String)
+        when {
+            x.length > 3 -> "long string"
+            else -> "short string"
+        }
+    else if (x is Int)
+        when {
+            x > 999 || x < -99 -> "long int"
+            else -> "short int"
+        }
+    else if (x is Long)
+        TODO()
+    else
+        "I don't know"
+}

idea/testData/intentions/branched/folding/ifToReturn/cascadeIf.kt

@@ -0,0 +1,17 @@
+// WITH_RUNTIME
+fun test(x: Any): String {
+    <caret>if (x is String)
+        when {
+            x.length > 3 -> return "long string"
+            else -> return "short string"
+        }
+    else if (x is Int)
+        when {
+            x > 999 || x < -99 -> return "long int"
+            else -> return "short int"
+        }
+    else if (x is Long)
+        TODO()
+    else
+        return "I don't know"
+}

idea/testData/intentions/branched/folding/ifToReturn/cascadeIf.kt.after

@@ -0,0 +1,17 @@
+// WITH_RUNTIME
+fun test(x: Any): String {
+    <caret>return if (x is String)
+        when {
+            x.length > 3 -> "long string"
+            else -> "short string"
+        }
+    else if (x is Int)
+        when {
+            x > 999 || x < -99 -> "long int"
+            else -> "short int"
+        }
+    else if (x is Long)
+        TODO()
+    else
+        "I don't know"
+}

idea/testData/intentions/branched/folding/whenToAssignment/cascadeWhen.kt

@@ -0,0 +1,16 @@
+// WITH_RUNTIME
+fun test(x: Any) {
+    var res: String
+    <caret>when (x) {
+        is String ->
+            if (x.length > 3) res = "long string"
+            else res = "short string"
+        is Int ->
+            if (x > 999 || x < -99) res = "long int"
+            else res = "short int"
+        is Long ->
+            TODO()
+        else ->
+            res = "I don't know"
+    }
+}

idea/testData/intentions/branched/folding/whenToAssignment/cascadeWhen.kt.after

@@ -0,0 +1,16 @@
+// WITH_RUNTIME
+fun test(x: Any) {
+    var res: String
+    <caret>res = when (x) {
+        is String ->
+            if (x.length > 3) "long string"
+            else "short string"
+        is Int ->
+            if (x > 999 || x < -99) "long int"
+            else "short int"
+        is Long ->
+            TODO()
+        else ->
+            "I don't know"
+    }
+}

idea/testData/intentions/branched/folding/whenToReturn/cascadeWhen.kt

@@ -0,0 +1,15 @@
+// WITH_RUNTIME
+fun test(x: Any): String {
+    <caret>when (x) {
+        is String ->
+            if (x.length > 3) return "long string"
+            else return "short string"
+        is Int ->
+            if (x > 999 || x < -99) return "long int"
+            else return "short int"
+        is Long ->
+            TODO()
+        else ->
+            return "I don't know"
+    }
+}

idea/testData/intentions/branched/folding/whenToReturn/cascadeWhen.kt.after

@@ -0,0 +1,15 @@
+// WITH_RUNTIME
+fun test(x: Any): String {
+    <caret>return when (x) {
+        is String ->
+            if (x.length > 3) "long string"
+            else "short string"
+        is Int ->
+            if (x > 999 || x < -99) "long int"
+            else "short int"
+        is Long ->
+            TODO()
+        else ->
+            "I don't know"
+    }
+}