Add ZTS Exceptions

[behlendorf]

Motivation and Context

Issue #12621, #12622, and #12623.

Description

Add the following test failures to the exception list for FreeBSD
to ensure we notice new unexpected failures.

pool_checkpoint/checkpoint_big_rewind
pool_checkpoint/checkpoint_indirect

And the following for Linux.

zvol/zvol_misc/zvol_misc_snapdev

How Has This Been Tested?

To be confirmed by the CI runs.

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.