message: gui tests: Limit life-time of dummy testing setup
  Its only purpose is to create a directory. So instead of keeping it
  alive, use it only to get the path of the directory and then create it
  explicitly.
diff: @@ -62,9 +62,10 @@ void AppTests::appTests()
  }
  #endif
  + fs::create_directories([] {
  BasicTestingSetup test{CBaseChainParams::REGTEST}; // Create a temp data directory to backup the gui settings to
  - ECC_Stop(); // Already started by the common test setup, so stop it to avoid interference
  - LogInstance().DisconnectTestLogger();
  + return GetDataDir() / "blocks";
  + }());
  m_app.parameterSetup();
  m_app.createOptionsModel(true /* reset settings */);
  @@ -80,6 +81,7 @@ void AppTests::appTests()
  m_app.exec();
  // Reset global state to avoid interfering with later tests.
  + LogInstance().DisconnectTestLogger();
  AbortShutdown();
  UnloadBlockIndex();
  WITH_LOCK(::cs_main, g_chainman.Reset());
  