[fix](warmup) fix warm up jobs missing last batch (#53860)

[kaijchen]

What problem does this PR solve?

Issue Number: DORIS-21591
Related PR: #53860

Problem Summary:

1. _pending_job_metas may be cleared by a CLEAR_JOB request, so we need to check it again.
2. We can not call pop_front before the job is finished, because GET_CURRENT_JOB_STATE_AND_LEASE is relying on the pending job size.

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
• Confirm test cases
• Confirm document
• Add branch pick label

[Thearas]

Thank you for your contribution to Apache Doris.
Don't know what should be done next? See How to process your PR.

Please clearly describe your PR:

1. What problem was fixed (it's best to include specific error reporting information). How it was fixed.
2. Which behaviors were modified. What was the previous behavior, what is it now, why was it modified, and what possible impacts might there be.
3. What features were added. Why was this function added?
4. Which code was refactored and why was this part of the code refactored?
5. Which functions were optimized and what is the difference before and after the optimization?

[kaijchen]

run buildall

[kaijchen]

run buildall

[freemandealer]

LGTM

[github-actions]

PR approved by anyone and no changes requested.

[github-actions]

PR approved by at least one committer and no changes requested.

[hello-stephen]

BE UT Coverage Report

Increment line coverage 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	41.90% (11136/26580)
Line Coverage	32.44% (95406/294129)
Region Coverage	31.57% (49264/156069)
Branch Coverage	28.00% (25249/90186)

[hello-stephen]

BE Regression && UT Coverage Report

Increment line coverage 0.00% (0/3) 🎉

Increment coverage report
Complete coverage report

Category	Coverage
Function Coverage	50.78% (13322/26234)
Line Coverage	41.24% (121136/293735)
Region Coverage	38.90% (70307/180737)
Branch Coverage	33.27% (33922/101952)

[dataroaring]

LGTM