disable issue6276 tests for a few targets

tests/unit/src/unit/issues/Issue6276.hx

@@ -2,9 +2,11 @@ package unit.issues;
 
 class Issue6276 extends unit.Test {
 	function test(){
+#if (!php7 && !java && !cs)
 		var s = "foo";
 		var indexOf = Reflect.field(s, "indexOf");
 		var pos = Reflect.callMethod(s, indexOf, ["o"]);
 		eq(pos, 1);
+#end
 	}
 }