Use an async checkpointer to initialize JDI in tests

[gobbleturk]

Description

According to this logic we only initialize the jax distributed system for an async checkpointer, but it looks like sometime recently in orbax this is needed even for a sync checkpointer. We should modify this logic but it may break some single host or pathways use cases which don't need the distributed system. A short term fix is to use an async checkpointer so that the jax distributed system is broken, e.g. for the end_to_end tests b/389730949

Tests

Ran gemma step 2 locally

Checklist

Before submitting this PR, please make sure (put X in square brackets):

• I have performed a self-review of my code.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run end-to-end tests tests and provided workload links above if applicable.
• I have made or will make corresponding changes to the doc if needed.

[khatwanimohit]

Thank you Matt!