See: #40002

This includes the bridgestrap stats parser.

This will depend on the version number as future versions may
include information we would not want to expose.

Hotfix for #40006.

As the docs say, "If timely disposal of file system resources is
required, the try-with-resources construct should be used to ensure
that the stream's close method is invoked after the stream operations
are completed."

Turns out that without closing the stream, the JVM runs out of memory
pretty quickly. Doing this is not optional but mandatory.

Implements #25307.

Implements #25309.

Part of #20542.

Part of #20542.

Part of #20542.

Replace all File references with their Path equivalents, and use Files
methods wherever feasible.

Part of #20542.

The separation between BridgeSnapshotReader, BridgeDescriptorParser,
and SanitizedBridgesWriter doesn't make much sense anymore:

 - BridgeSnapshotReader only has a constructor of more than 200 lines
   of code.

 - BridgeDescriptorParser actually only determines the descriptor type
   and

 - SanitizedBridgesWriter performs parsing and obfuscation.

There are better ways to structure this code. The first step in that
direction is to remove clutter by moving the code to read bridge
snapshots to SanitizedBridgesWriter and deleting the other two
classes.

Part of #20542.

The indexer did not handle a (mostly theoretic) edge case of a file
being moved away and then moved back shortly after. In such a case the
file should not be marked for deletion anymore and it should be
included in the index again. That's what this commit does.

The other minor changes to unit tests are just cosmetic.

Fixes #34030.

One of the previously made changes to cleaning up directories was that
empty directories were deleted. This was necessary, because otherwise
there would be a growing number of directories as files get deleted
after reaching an age of seven weeks.

However, this change should not have included deleting the cleaned up
directory itself. In practice, this will not happen. But in tests it's
certainly possible that a directory is empty and then gets deleted.
This leads to all sorts of problems in tests.

The fix is to limit deleting empty directories to subdirectories.
That's what this commit does.

Fixes #21219.