[fix](regression) Drop view before its base tables in test_join5

[shuke987]

What problem does this PR solve?

Issue Number: DORIS-23587

Related PR: None

Problem Summary:

test_join5 creates the uqv1 view on top of uq1, but drops uq1 while the view still exists. A concurrent information_schema.view_dependency scan can observe this dangling view and fail while resolving its missing base table.

This change drops uqv1 after its last assertion and before dropping its base tables, so the case does not expose an invalid intermediate state to concurrently running regression suites.

Release note

None

Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
    • git diff --check
    • Parsed test_join5.groovy with GroovyShell; result: PASS.
  • 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

[hello-stephen]

Thank you for your contribution to Apache Doris.
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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?

[shuke987]

run buildall

[shuke987]

/review

[github-actions]

Reviewed the one-file regression cleanup in test_join5.groovy. The added DROP VIEW IF EXISTS ${tbName7}; runs after the last query that uses uqv1 and before the base tables are dropped, which matches the stated information_schema.view_dependency dangling-view hazard. The expected output remains correctly unchanged because the added statement has no result set.

Critical checkpoint conclusions:

• Goal/test proof: The PR is a focused cleanup for test_join5; the existing qt_join4 output remains covered by test_join5.out, and the new statement is cleanup-only.
• Scope: The change is small and isolated to one regression suite.
• Concurrency/lifecycle: No new runtime concurrency is introduced; the relevant concurrency point is that the suite no longer leaves a view visible after its base table cleanup begins.
• Compatibility/config/persistence/protocol: No FE/BE protocol, persisted format, session/config, or rolling-upgrade behavior changes.
• Parallel paths: No parallel changed path needs an update for this regression-only cleanup.
• Tests/results: The .out file is unchanged, which is appropriate because DROP VIEW produces no query output.

User focus: No additional user-provided review focus was supplied.

Subagent conclusions: optimizer-rewrite found no optimizer, semantic-equivalence, join/aggregate, or view-planner candidate. tests-session-config found no regression-output, session/config, compatibility, or CI/style candidate. Convergence round 1 ended with both live subagents reporting NO_NEW_VALUABLE_FINDINGS for the same ledger/comment set, and no inline comments were accepted.

Validation limits: Static review only in this runner. The checkout is grafted/shallow, .worktree_initialized, thirdparty/installed, and output are absent, and groovy is not installed, so I did not run the regression suite locally. I did run git show --check --format=medium HEAD -- regression-test/suites/query_p0/join/test_join5.groovy, which reported no whitespace errors.