Corrected oversight in ZERO_RANGE behavior - 2.1 backport

[behlendorf]

Motivation and Context

Backport of #13338 for the zfs-2.1.5-staging branch.

Description

    Corrected oversight in ZERO_RANGE behavior
    
    It turns out, no, in fact, ZERO_RANGE and PUNCH_HOLE do
    have differing semantics in some ways - in particular,
    one requires KEEP_SIZE, and the other does not.
    
    Also added a zero-range test to catch this, corrected a flaw
    that made the punch-hole test succeed vacuously, and a typo
    in file_write.

How Has This Been Tested?

Clean cherry pick, see #13338 for additional details.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.