lib,src: switch Buffer::kMaxLength to size_t

Change the type of Buffer::kMaxLength to size_t because upcoming changes in V8 will allow typed arrays > 2 GB on 64 bits platforms.

Not all platforms handle file reads and writes > 2 GB though so keep enforcing the 2 GB typed array limit for I/O operations.

Fixes: https://github.com/nodejs/node/issues/31399 Refs: https://github.com/libuv/libuv/pull/1501