CI/CD UT optimization

[charlesli640]

Description

Move AotJaxprIdenticalTest to sheduled_only due to long time consuming
Work-around b/454659463

Relabel test_diloco_two_slices train_compile test as cpu_only/tpu_backend to save tpu comsuming

Tests

CI/CD workflow

Checklist

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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