Fix all-empty input column for strings split APIs

[davidwendt]

Description

Fixes specialized behavior for all empty input column on the strings split APIs.
Verifying behavior with Pandas str.split( pat, expand, regex )
pat=None -- whitespace
expand=False -- record APIs
regex=True -- re APIs

• split
• split - whitespace
• rsplit
• rsplit - whitespace
• split_record
• split_record - whitespace
• rsplit_record
• rsplit_record - whitespace
• split_re
• rsplit_re
• split_record_re
• rsplit_record_re

Closes #16453

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[bdice]

Just to verify — this aligns with pandas behavior, but what about Spark? Code looks fine otherwise.

[davidwendt]

Just to verify — this aligns with pandas behavior, but what about Spark? Code looks fine otherwise.

Good point. I forgot to add the original issue which came from Spark.
#16453
@ttnghia Can you verify this will be OK for Spark?

[ttnghia]

Spark integration tests (after reverting workaround for empty strings due to issue #16453) all passed with this work 👍

[davidwendt]

/merge