Convert to block body: when expression with Unit result is now handled as "return needed" #KT-12193 Fixed

idea/testData/intentions/convertToBlockBody/ifWhenUnit.kt.after

@@ -0,0 +1,14 @@
+enum class AccessMode { READ, WRITE, EXECUTE }
+
+fun foo() {}
+
+fun whenExpr(access: AccessMode, arg: Boolean) {
+    return if (arg) {} else {
+        foo()
+        when (access) {
+            AccessMode.READ -> {}
+            AccessMode.WRITE -> {}
+            AccessMode.EXECUTE -> {}
+        }
+    }
+}