message: tweak test matrix: test big-endian, and test less on macOS host (it is slow)
diff: @@ -43,9 +43,8 @@ if [ "${TRAVIS_OS_NAME:-}" == linux ]; then
  MIRI_TEST_TARGET=x86_64-apple-darwin run_tests
  MIRI_TEST_TARGET=i686-pc-windows-msvc run_tests
  elif [ "${TRAVIS_OS_NAME:-}" == osx ]; then
  - MIRI_TEST_TARGET=i686-unknown-linux-gnu run_tests
  + MIRI_TEST_TARGET=mips64-unknown-linux-gnuabi64 run_tests # big-endian architecture
  MIRI_TEST_TARGET=x86_64-pc-windows-msvc run_tests
  - MIRI_TEST_TARGET=i686-pc-windows-gnu run_tests
  elif [ "${CI_WINDOWS:-}" == True ]; then
  MIRI_TEST_TARGET=x86_64-unknown-linux-gnu run_tests
  MIRI_TEST_TARGET=x86_64-apple-darwin run_tests
  