[Wasm] Add test for KT-49182

compiler/testData/codegen/box/controlStructures/returnsNothing/ifElse.kt

@@ -1,8 +1,20 @@
+// IGNORE_BACKEND: WASM
+// WASM_MUTE_REASON: STRANGE_IMPLICIT_CAST
+
+fun kt49182(x: Boolean): String {
+    return if (x) {
+        return "O"
+    } else "K"
+}
+
 var flag = true
 
 fun exit(): Nothing = null!!
 
 fun box(): String {
+    if (kt49182(true) + kt49182(false) != "OK")
+        return "Fail test2"
+
     val a: String
     if (flag) {
         a = "OK"