#35442 test: remove usages of MAX_BIP125_RBF_SEQUENCE constant from functional tests

• Align test framework helpers with current mempool policies as opt-in RBF signaling is phased out
• Cleans up outdated BIP 125 sequence constants across functional tests for test maintainers

This pull request removes the `MAX_BIP125_RBF_SEQUENCE` constant from the functional test framework (`messages.py`) and replaces or removes its references across non-wallet and wallet functional tests. It is stacked on top of unmerged wallet/RPC deprecation changes from #35433 and #35405, which make up the bulk of the diff.

Problem: Tests were still referencing the BIP 125 sequence constant even though the project is moving away from opt-in RBF signaling. Test authors and maintainers benefit from keeping test framework helpers aligned with current mempool policies.

P4 · cleanup

• P4 because this is a minor test cleanup removing an unused test framework constant
• Does not fix test flakiness or expand test coverage

P4 because this is minor test code cleanup. Removing an unused test framework constant and updating call sites does not fix test flakiness or expand test coverage.

Membership: Touches test/functional/test_framework/messages.py to remove MAX_BIP125_RBF_SEQUENCE and adjusts multiple functional tests.

Factors: security/stability 0, bug 0, performance 0, user value 0, leverage 1

• Review #35405 and #35433 first
• Needs rebase due to merge conflicts and author has been inactive for over 90 days

The PR has merge conflicts and the author has been inactive for over 90 days while waiting on base PRs.

Author status: silent since 2026-06-10

Open concerns:

• maflcko asked whether this small test fixup should be folded directly into #35433 rather than existing as a standalone PR

• No reviews or approvals yet
• Suggested folding this small test fixup directly into the parent pull request (maflcko)

No reviews or ACKs; maflcko asked if the commits belong in the parent PR

Nobody has reviewed or supported the PR as a standalone change, and maflcko questioned why it was not included in the prior pull request.

• maflcko asked: 'Not sure if a small test-only fixup needs a separate pull request. Can those two commits not just be included in the prior pull?'
• rkrux attempted to fold them into #35433 but encountered dependencies on #35405, then stated they would wait on #35405 resolution.

Review verdicts (DrahtBot): 0

Depends on: #35405, #35433

605 lines under test/bench/ci.

• test/functional/wallet_bumpfee.py +231/-235
• test/functional/wallet_deprecated_rbf.py +70/-5
• src/wallet/rpc/spend.cpp +41/-20
• test/functional/mempool_package_rbf.py +13/-13
• doc/release-notes-34917.md +20/-4
• src/rpc/rawtransaction.cpp +9/-5
• test/functional/rpc_psbt.py +5/-5
• test/functional/rpc_packages.py +2/-3
• test/functional/rpc_rawtransaction.py +0/-5
• test/functional/feature_rbf.py +2/-2
• test/functional/p2p_opportunistic_1p1c.py +2/-2
• test/functional/wallet_listsinceblock.py +1/-3
• test/functional/mempool_accept.py +1/-2
• src/rpc/rawtransaction_util.cpp +1/-1
• src/wallet/spend.cpp +1/-1
• src/wallet/wallet.h +1/-1
• test/functional/p2p_segwit.py +0/-2
• test/functional/test_framework/messages.py +0/-1

PR #35442 removes the MAX_BIP125_RBF_SEQUENCE constant from the Python test framework and updates test callers as part of ongoing BIP 125 deprecation. Only two commits belong to this PR, with the preceding eleven commits inherited from unmerged base PRs #35405 and #35433. The change is minor test cleanup with no external user impact. It is currently stale, in draft, has merge conflicts, and reviewers questioned whether it should exist as a separate PR.