ax(batch): add missing test files and fix pre-existing test compilation errors
Adds test files for 6 source files that had no corresponding test:
bufpool_test.go (mining + node), metrics_test.go, version_test.go,
supervisor_test.go, mining_profile_test.go. Each follows
TestFilename_Function_{Good,Bad,Ugly} convention.
Also fixes 2 pre-existing compilation errors:
- ratelimiter_test.go: rl -> rateLimiter (leftover from AX rename)
- worker_test.go: worker.node -> worker.nodeManager (field was renamed)
Co-Authored-By: Charon <charon@lethean.io>
63a9107f9c