Reject constructors called as function (i.e. without 'new')

Previously, `MessageEvent('')` would have been allowed, but invalid. This caused
problems as the receiver was the window. All such calls are now rejected.

Depends on https://github.com/lightpanda-io/zig-v8-fork/pull/131

src/browser/js/Caller.zig

@@ -89,6 +89,10 @@ pub const CallOpts = struct {
 };
 
 pub fn constructor(self: *Caller, comptime T: type, func: anytype, info: v8.FunctionCallbackInfo, comptime opts: CallOpts) void {
+    if (!info.isConstructCall()) {
+        self.handleError(T, @TypeOf(func), error.InvalidArgument, info, opts);
+        return;
+    }
     self._constructor(func, info) catch |err| {
         self.handleError(T, @TypeOf(func), err, info, opts);
     };