Restore stack-like behavior of parseGLIF transform pointer

[skef]

Also Fix ancient transform->isDefault logic error.

Description

What it says on the tin.

Checklist:

• I have followed the Contribution Guidelines
• I have added test code and data to prove that my code functions correctly
• I have verified that new and existing tests pass locally with my changes
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation

[cjchapman]

👍

Note about the test failures:

There seems to be some new issue with the (macos-latest, 3.10) tests, but as far as I can tell, it's a CI issue, and not a code issue. The tests passed locally on my M1 mac with Python 3.10.8.

There's also an older CI issue with the (windows-latest, 3.10) tests (see #1581).