[tests] add test (closes #3878)

tests/optimization/src/issues/Issue3878.hx

@@ -0,0 +1,11 @@
+package issues;
+
+class Issue3878 {
+	@:js('
+		var v = "hello";
+	')
+	@:analyzer(no_const_propagation, no_local_dce)
+	static function test() {
+        var v = (function(id) return id : String->String)("hello");
+	}
+}