[CALCITE-3648] MySQL UNCOMPRESS function support

[ritesh-kapoor]

https://dev.mysql.com/doc/refman/8.0/en/encryption-functions.html#function_uncompress

e.g.:

SELECT UNCOMPRESS(COMPRESS('any string')); -> 'any string' SELECT UNCOMPRESS('any string'); -> NULL Uncompresses a string compressed by the COMPRESS() function. If the argument is not a compressed value, the result is NULL. This function uses zlib library for decompression (https://docs.oracle.com/javase/8/docs/api/java/util/zip/Inflater.html). Otherwise, the return value is always NULL.

[XuQianJin-Stars]

hi, @ritesh-kapoor Can this PR add a description?

[ritesh-kapoor]

hi, @ritesh-kapoor Can this PR add a description?

Added.. Thanks

[ritesh-kapoor]

All the review comments are resolved. Please let me know if something else is pending