avoid prototype builtin hasOwnProperty

[justjavac]

prototype builtin hasOwnProperty for two problems:

1. if the object has a key named hasOwnProperty:

   const options = {"hasOwnProperty":"foo" };
   new Blob(["hello"], options);

   throw

   Uncaught TypeError: options.hasOwnProperty is not a function
       at DenoBlob (js/blob.ts:94:18)
       at <unknown>:1:1
       at evaluate (js/repl.ts:87:34)
       at replLoop (js/repl.ts:145:13)
   

2. the object doesn't inherit from Object.prototype:

   const options = Object.create(null);
   new Blob(["hello"], options);

   throw

   Uncaught TypeError: options.hasOwnProperty is not a function
       at DenoBlob (js/blob.ts:94:18)
       at <unknown>:1:1
       at evaluate (js/repl.ts:87:34)
       at replLoop (js/repl.ts:145:13)
   

[ry]

LGTM - thanks : )