[query] Improve error message from hadoop_ls when file does not exist

[nawatts]

As described in #9600, hl.hadoop_ls currently raises a NullPointerException when called with a path that does not exist. The error originates in is.hail.io.fs.HadoopFS.listStatus.

The hadoop.fs.FileSystem docs list two forms of globStatus:

• public FileStatus[] globStatus(Path pathPattern)
• public FileStatus[] globStatus(Path pathPattern, PathFilter filter)

The first makes no mention of returning null. The second however, says:

Returns: null if pathPattern has no glob and the path does not exist an empty array if pathPattern has a glob and no path matches it else an array of FileStatus objects matching the pattern

This matches the behavior seen with hl.hadoop_ls.

This change checks for a null value returned from globStatus and raises a FileNotFoundException in that case.

Resolves #9600

[nawatts]

Scorecard returned @johnc1231

[johnc1231]

Great fix, thank you!