Re-enable x86_64 Windows CI build

.github/workflows/ci.yml

@@ -116,7 +116,7 @@ jobs:
           - { target: i686-unknown-linux-musl     , os: ubuntu-20.04, use-cross: true }
           - { target: x86_64-apple-darwin         , os: macos-12                      }
           #- { target: x86_64-pc-windows-gnu       , os: windows-2019                  }
-          # - { target: x86_64-pc-windows-msvc      , os: windows-2019                  } -- currently disabled because of a flaky unit test
+          - { target: x86_64-pc-windows-msvc      , os: windows-2019                  }
           - { target: x86_64-unknown-linux-gnu    , os: ubuntu-20.04, use-cross: true }
           - { target: x86_64-unknown-linux-musl   , os: ubuntu-20.04, use-cross: true }
     env: