Take control flow into account for checking fall-through switch branches

#KT-16133 Fixed

j2k/testData/fileOrElement/switch/nestedIf.java

@@ -0,0 +1,15 @@
+//method
+public String foo(int i, int j) {
+    switch (i) {
+        case 0:
+            if (j > 0) {
+                return "1"
+            } else{
+                return "2"
+            }
+        case 1:
+            return "3";
+        default:
+            return "4";
+    }
+}

j2k/testData/fileOrElement/switch/nestedIf.kt

@@ -0,0 +1,11 @@
+fun foo(i: Int, j: Int): String {
+    when (i) {
+        0 -> if (j > 0) {
+            return "1"
+        } else {
+            return "2"
+        }
+        1 -> return "3"
+        else -> return "4"
+    }
+}

j2k/testData/fileOrElement/switch/nestedIfFallback.java

@@ -0,0 +1,13 @@
+//method
+public String foo(int i, int j) {
+    switch (i) {
+        case 0:
+            if (j > 0) {
+                return "1"
+            }
+        case 1:
+            return "2";
+        default:
+            return "3";
+    }
+}

j2k/testData/fileOrElement/switch/nestedIfFallback.kt

@@ -0,0 +1,12 @@
+fun foo(i: Int, j: Int): String {
+    when (i) {
+        0 -> {
+            if (j > 0) {
+                return "1"
+            }
+            return "2"
+        }
+        1 -> return "2"
+        else -> return "3"
+    }
+}

j2k/testData/fileOrElement/switch/nestedSwitch.java

@@ -0,0 +1,16 @@
+//method
+public String foo(int i, int j) {
+    switch (i) {
+        case 0:
+            switch (j) {
+                case 1:
+                    return "0, 1";
+                default:
+                    return "0, x";
+            }
+        case 1:
+            return "1, x";
+        default:
+            return "x, x";
+    }
+}

j2k/testData/fileOrElement/switch/nestedSwitch.kt

@@ -0,0 +1,10 @@
+fun foo(i: Int, j: Int): String {
+    when (i) {
+        0 -> when (j) {
+            1 -> return "0, 1"
+            else -> return "0, x"
+        }
+        1 -> return "1, x"
+        else -> return "x, x"
+    }
+}

j2k/testData/fileOrElement/switch/nestedSwitchFallback.java

@@ -0,0 +1,15 @@
+//method
+public String foo(int i, int j) {
+    switch (i) {
+        case 0:
+            switch (j) {
+                case 1:
+                    return "0, 1";
+                case 2:
+                    return "0, 2";
+            }
+        case 1:
+            return "1, x";
+        default:
+            return "x, x";
+}

j2k/testData/fileOrElement/switch/nestedSwitchFallback.kt

@@ -0,0 +1,13 @@
+fun foo(i: Int, j: Int): String {
+    when (i) {
+        0 -> {
+            when (j) {
+                1 -> return "0, 1"
+                2 -> return "0, 2"
+            }
+            return "1, x"
+        }
+        1 -> return "1, x"
+        else -> return "x, x"
+    }
+}