Problem:

There are some inconsistencies in how we handle tar archives:

1. provisionersdk.Tar adds symlinks without de-referencing them
2. provisionersdk.Untar does not handle symlinks at all as far as I can tell
3. provisionerd does not actually use provisionersdk.Untar to extract archives; it uses a separate implementation (*provisionersdk.Session).extractArchive()

Proposed solution:

• Bring the behaviour of provisionersdk.Untar in line with extractArchive()
• Replace existing usage of extractArchive() with provisionersdk.Untar
• Clarify behaviour regarding symlinks -- given that we currently do not extract them, it does not make sense to continue the existing dereferencing behaviour in provisionersdk.Tar().

Originally posted by @johnstcn in #16128 (comment)