[1.7.x] Moved version directives to the bottom of the loaddata section.

Backport of 6403e07c5093e0244497293f31f5f73cebe85b66 from master
[1.7.x] Made model_regress unpickling test CWD-independent

Refs #24007. Thanks Tim Graham for his help with the patch.

Backport of 1d9fc5caa947ff4ee72180185e91a9a145171712 and
995be4a1375340a53668dd80444756d77302000d from master
[1.7.x] Added upgrade instructions for deprecated model _meta permission methods.

Backport of a3d96bee36040975ded8e3bf02e33e48d06f1f16 from master