Support missing when branch exception throwing. (#174)

backend.native/tests/build.gradle

@@ -287,6 +287,11 @@ task when7(type: RunKonanTest) {
     source = "codegen/branching/when7.kt"
 }
 
+task when8(type: RunKonanTest) {
+    source = "codegen/branching/when8.kt"
+    goldValue = "true\n"
+}
+
 task when_through(type: RunKonanTest) {
     source = "codegen/branching/when_through.kt"
 }

backend.native/tests/codegen/branching/when8.kt

@@ -0,0 +1,6 @@
+fun main(args: Array<String>) {
+    when (true) {
+        true -> println("true")
+        false -> println("false")
+    }
+}