coreutils: dummy -> true -> coreutils symlink chain runs as true

[oech3]

This adds an extension to resolve symlink chain:
dummy runs as true with dummy -> true -> coreutils.

This is needed to cover the usecase to symlink true to other binary to spoof some scripts. It is possible with individual binaries, but Ubuntu uses multi-call binary for binary size issue at least for.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/misc/coreutils. tests/misc/coreutils is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/resolution (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/cut/bounded-memory is now being skipped but was previously passing.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/misc/coreutils. tests/misc/coreutils is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/resolution (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/resolution (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/tail/symlink (fails in this run but passes in the 'main' branch)
Note: The gnu test tests/env/env-signal-handler was skipped on 'main' but is now failing.