[Feature Request][move-compiler-v2] warn about compilation input files that seem to be redundant

[brmataptos]

🚀 Feature Request

As discussed in #13216, we think there are certain cases where different or multiple versions of the same file may be found by move-package searches for Move compilation dependencies. It's not clear that this is feasible, but we should add a mechanism to check for redundant packages and/or very similar files (perhaps just identical file names, or last-level directory + filename) and warn about them during compilation, especially if an error occurs.

This could be accompanied by suggestions to run aptos move clean or move clean in dependency directories, or deleting build/ directories.

[brmataptos]

Note that move_command_line_common::files::find_move_filenames is used to find source files recursively, given a list of package directories and/or move source files. The list of dependent packages should be handled differently when this was called, appending "/source" to any directory name so that files in other subdirs are not grabbed, such as test dirs that may contain a lot of unrelated files.

It is more awkward to do this in callers, since the list can have files (which should be kept unchanged) and directories (which should be modified for the case of deps), but this is an API change so maybe a separate function should be created.

I've spawned a new issue to deal with this: #13361, while leaving this one to track a feature which would be lower priority if we fix that one.