treat fields with initializers as optional when checking object liter…

…als and structInit (fix tests)

src/test/resources/testData/annotation.semantic/AssignStructInit.hx

@@ -2,7 +2,8 @@ package;
 @:structInit class MyStruct {
   //NOTE: should not show warning about final when in structInit class
   final name:String;
-  var age:Int = 30;
+  var age:Int;
+  var height:Float = 3.0; // init = same as optional
   @:optional var address:String;
 
 }
@@ -11,7 +12,7 @@ class Test {
   public function new() {
     // correct
     var s1:MyStruct = {name:"name", age:30};
-    var s2:MyStruct = {name:"name", age:30, address:"address 1"};
+    var s2:MyStruct = {name:"name", age:30, height:1.0, address:"address 1"};
 
     // wrong (TODO better error messages)
     var <error descr="Incompatible type: {...} should be MyStruct">s3:MyStruct = {name:"name"}</error>; // missing field