Environment: MSYS_BITS=64, SCRIPT=python x.py test, RUST_CONFIGURE_ARGS=--build=x86_64-pc-windows-gnu --enable-ninja, MINGW_URL=https://s3.amazonaws.com/rust-lang-ci/rust-ci-mirror, MINGW_ARCHIVE=x86_64-6.2.0-release-win32-seh-rt_v5-rev1.7z, MINGW_DIR=mingw64