Non-acid to acid conversion doesn't handle random filenames

Right now the supported filename patterns for non-acid to acid table's files (original files) are the only ones created by Hive itself (eg. 000000, 000000_COPY_1, bucket_00000, etc). But at the same time Hive non-acid table supports reading from tables having files with random filenames. We should support the same for acid tables.

A way to handle this would be to rename such files and though rename is not a costly operation for HDFS, But for non-acid tables with the location on a blobstore like s3 and having random filenames will have costly added steps to convert to acid.

Current scenario: What we do now for original files is assign them a logical bucket id and for unrecognized patterns we assign -1 and ignore those files.

Proposed alternatives:

1) For all the random files assume the logical bucket id as 0 and let the files belong to the same bucket in the way similar to we do for multiple files with same bucket id (_copy_N).
2) For all the random files lexicographically sort them and sequentially assign them a bucket id similar to the handling of multiple files for a non-bucketed table where we extract the bucket id simply from filenames