Make serialize() throw if same buffer and byteOffset are given

[ibc]

I cannot explain it better than I've done in the code and tests.

NOTES

We cannot do much magic here, and we should not make happy assumptions. For example, in Node.js when you create a Node native Buffer instance using Buffer.allocUnsafe(), its buffer member (an ArrayBuffer instance where the bytes really are) is a **very big allocated ArrayBuffer instance. If you later create another Node native Buffer then its .buffer member will be the same as in the previous one, however the byteOffset and so off are different:

> b1 = Buffer.allocUnsafe(10)
// <Buffer 00 00 00 00 00 00 00 00 00 00>

> b1.buffer
// ArrayBuffer {
//   [Uint8Contents]: <2f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
//    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
//    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
//    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 
//    ...8092 more bytes>,
//   byteLength: 8192
// }

> b2 = Buffer.allocUnsafe(10)
// <Buffer 00 00 00 00 00 00 00 00 00 00>

> b2.buffer
// ArrayBuffer {
//   [Uint8Contents]: <2f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
//    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
//    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
//    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
//    ... 8092 more bytes>,
//   byteLength: 8192
// }

> b1.buffer === b2.buffer
// true

> b1.byteOffset === b2.byteOffset
// false