Copy va_list for second use (and add va_end's to avoid leaking)

[skef]

Description

The error-printing code first tries to use a 128 byte buffer for output and then resizes if that fails. This code was mistakenly assuming the va_list wasn't altered as part of the call. This PR makes a copy va_list in case it is needed. It also adds va_end calls that were mistakenly left out of the original PR.

Closes #1504

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

[josh-hadley]

👍