Improve exit signal related log message

[eval-exec]

What problem does this PR solve?

When ckb received exit signal multiple times, it will print:

error!("send exit signal to channel failed since the channel is full, this should not happen")

This shouldn't be an ERROR level log, should downgrade the log level from ERROR to INFO.

What's Changed:

Related changes

• Downgrade log level from ERROR to INFO when ckb received exit signal multiple time.
• Upgrade exit signal related log from DEBUG to INFO

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code ci-runs-only: [ quick_checks,linters ]

Side effects

• None

Release note

None: Exclude this PR from the release note.

[chenyukang]

also change debug!("wait thread {} done", name); to info?

[eval-exec]

Agree. 💙

[eval-exec]

The unit test test_should_have_no_output_in_cellbase_no_finalization_target failed,
caused by pthread lock: Invalid argument

     SIGABRT [   0.846s] ckb-verification-contextual tests::contextual_block_verifier::test_should_have_no_output_in_cellbase_no_finalization_target

--- STDOUT:              ckb-verification-contextual tests::contextual_block_verifier::test_should_have_no_output_in_cellbase_no_finalization_target ---

running 1 test
test tests::contextual_block_verifier::test_should_have_no_output_in_cellbase_no_finalization_target ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 17 filtered out; finished in 0.71s


--- STDERR:              ckb-verification-contextual tests::contextual_block_verifier::test_should_have_no_output_in_cellbase_no_finalization_target ---
pthread lock: Invalid argument

error: test run failed
make: *** [test] Error 100
Error: Process completed with exit code 2.