Delete temporary build directory after compilation

[alranel]

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• Tests for the changes have been added (for bug fixes / features)
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• What kind of change does this PR introduce?

Bug fix (somewhat).

• What is the current behavior?

The temporary build directory created by arduino-cli compile is not deleted when the process is done. When running many jobs, the impact on free disk space can be visible.

• What is the new behavior?

The temporary build directory is deleted when compilation is done.

• Does this PR introduce a breaking change, and is
  titled accordingly?

No breaking change.

• Other information:

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[ubidefeo]

@alranel
If I'm not wrong this directory is the one containing files used for Language Server and Debugger.
@cmaglie and @silvanocerza can you confirm?

[silvanocerza]

I confirm what @ubidefeo is saying. I don't think we should make this change, all in all I think it has been an improvement.

We could offer a way for user to delete all those temporary folders though. There's already a cache clean command, we could take advantage of it to also delete all arduino-sketch-<md5_hash> in the temp folder.

[PaulStoffregen]

Perhaps the oldest leftover temporary files could be found and deleted? It could be based on the file age, or space used, or both. A few people might not want any files left over, but probably most people just wish to avoid boundless growth over long term use.

[ubidefeo]

@silvanocerza @PaulStoffregen
one would assume that an Operating System deleted files in temporary folders every now and then.
I think we could leverage cache clean to do that

[alranel]

Gotcha. I was under the erroneous assumption that everything we store under /tmp are temporary files but I understand we're also storing cache files there. I believe there are more standard places where to store cache files, such as ~/Library/Caches on macOS and ~/.cache on Linux, and there's also a XDG_CACHE_HOME env variable.

Apart from location, maybe using the prefix arduino-cache- in combination with the proposed cache clean command could help.

(Feel free to close this pull request of course)