Respect file order in DocumentDataset.read_

[praateekmahajan]

Description

By removing the sorted(..) in read_data_files_per_partition we can be sure that the input order provided by user is respected. And in case a directory is provided as an input then we are ls-ing and then sorting before reading.

Solves #486

Current Code Flow

Current flow is

1. DocumentDataset.read_json/parquet calls _read_json_or_parquet
2. _read_json_or_parquet which calls read_data
   • _read_json_or_parquet accepts input_files that could be list[files], list[dir] or file or dir
   • if it's a dir or list[dir] it calls get_all_files_paths_under which has an implicit sort
3. read_data accepts list[files] and calls read_data_blocksize or read_data_files_per_partition`
4. 1. read_data_files_per_partition performs a sort
   2. read_data_blocksize doesn't perform a sort

Usage

# Add snippet demonstrating usage

Checklist

• I am familiar with the Contributing Guide.
• New or Existing tests cover these changes.
• The documentation is up to date with these changes.

[sarahyurick]

Good with me, was actually wondering why that was there earlier today lol.