message: do not enable expensive-debug-assertions in installed Miri in CI
diff: #!/bin/bash
  set -euo pipefail
  +set -x
  # Determine configuration
  export RUSTFLAGS="-D warnings"
  export CARGO_INCREMENTAL=0
  -export CARGO_EXTRA_FLAGS="--all-features"
  +export CARGO_EXTRA_FLAGS="--all-features" # in particular, expensive-debug-assertions
  # Prepare
  echo "Build and install miri"
  -./miri build --all-targets --locked
  -./miri install # implicitly locked
  +CARGO_EXTRA_FLAGS="" ./miri install # implicitly locked -- and the *installed* Miri does *not* get the expensive-debug-assertions feature
  +./miri build --all-targets --locked # the build that all the `./miri test` below will use
  echo
  # Test
  