Removed old test runner test cases.

These files were added as part of #12658, which pertained to the old django.test.simple test runner. No tests call them anymore.
Fixed monkeypatching in a staticfiles test.
Fixed migrate when called inside a transaction.

This is useful for tests manually calling migrate inside a testcase,
for normal usage this should make no difference, since there is no
surrounding transaction after all. If there is one we still try to
leave the transaction in a useable state (for postgres at least).

If this commit turns out to be causing issues, settings savepoint=False
is probably the right fix :)
Merge pull request #2592 from prestontimmons/remove-test-runner-cases

Removed old test runner test cases.
Corrected the section identifier for MySQL unicode reference.
Fixed adding new GIS column in PostGIS 1.x migration

Refs #22451.
Fixed removal of GIS column in PostGIS 1.x migration

Refs #22481.
Fixed PostGIS remove_field implementation

Fixed bad code introduced in 2f9d1576e8.
Fixed table cleanup in GIS migration tests
Fixed a remote code execution vulnerabilty in URL reversing.

Thanks Benjamin Bach for the report and initial patch.

This is a security fix; disclosure to follow shortly.
Prevented leaking the CSRF token through caching.

This is a security fix. Disclosure will follow shortly.
Fixed queries that may return unexpected results on MySQL due to typecasting.

This is a security fix; disclosure to follow shortly.
Added information on resolved security issues to release notes.