Appeased spell checker.
Cleanup cache in contrib.sites to prevent test interference -- refs #11505
Refs #18586 -- Split custom_pk test.
Refs #18586 -- Split custom manager tests.
Readded test inadvertently removed in last commit.
Refs #18586 -- Refactored expressions tests.
Fixed #23674 -- Fixed a crash when a MultiValueField has invalid data.
Refs #20392 -- Load fixtures once within TestCase
Fixed template tag braces spacing.
Fixed #23941 -- Removed implicit decimal formatting from expressions.
Fixed #23857 -- Fixed admin crash with "save as new" and deleting inline.

Thanks amarandon for the report.
Revert "Fixed #23455 -- Forced related_name to be a unicode string during deconstruction."

This reverts commit 45bd7b3bd9008941580c100b9fc7361e3ff3ff0d.
Fixed #23982 -- Added doc note on generating Python 2/3 cross-compatible migrations.

Thanks Luke Plant for the report, and Tim Graham, Simon Charette, and Markus
Holtermann for review and discussion.
Fixed #23455 -- Accept either bytes or text for related_name, convert to text.