Merge bitcoin/bitcoin#31187: ci: Do not error on unused-member-function in test each commit

54d07dd37d ci: Do not error on unused-member-function in test each commit (Sergi Delgado Segura)

Pull request description:

  After https://github.com/bitcoin/bitcoin/pull/31045, an unused method in a commit will trigger a compilation error, even if that method is later used in a following commit within the same PR.

  Do not enforce unused-member-function in test each commit.

  Close #31180

ACKs for top commit:
  kevkevinpal:
    lgtm ACK [54d07dd](54d07dd37d)
  maflcko:
    lgtm ACK 54d07dd37d
  TheCharlatan:
    lgtm ACK 54d07dd37d

Tree-SHA512: 79723ca604d44b065b08793b442de9049a689cc5a4df508299a91966456bf77e24a0f3febaf3114fd23b061716554b70ee866bf594283960d952366ea2096dbc

.github/workflows/ci.yml

@@ -72,7 +72,7 @@ jobs:
         run: |
           # Run tests on commits after the last merge commit and before the PR head commit
           # Use clang++, because it is a bit faster and uses less memory than g++
-          git rebase --exec "echo Running test-one-commit on \$( git log -1 ) && CC=clang CXX=clang++ cmake -B build -DWERROR=ON -DWITH_ZMQ=ON -DBUILD_GUI=ON -DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON -DWITH_BDB=ON -DWITH_USDT=ON && cmake --build build -j $(nproc) && ctest --output-on-failure --test-dir build -j $(nproc) && ./build/test/functional/test_runner.py -j $(( $(nproc) * 2 ))" ${{ env.TEST_BASE }}
+          git rebase --exec "echo Running test-one-commit on \$( git log -1 ) && CC=clang CXX=clang++ cmake -B build -DWERROR=ON -DWITH_ZMQ=ON -DBUILD_GUI=ON -DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON -DWITH_BDB=ON -DWITH_USDT=ON -DCMAKE_CXX_FLAGS='-Wno-error=unused-member-function' && cmake --build build -j $(nproc) && ctest --output-on-failure --test-dir build -j $(nproc) && ./build/test/functional/test_runner.py -j $(( $(nproc) * 2 ))" ${{ env.TEST_BASE }}
 
   macos-native-arm64:
     name: 'macOS 14 native, arm64, no depends, sqlite only, gui'