Stabilize the "nix-command" feature

tests/functional/config.sh

@@ -54,8 +54,8 @@ var=$(nix config show | grep '^allowed-uris =' | cut -d '=' -f 2 | xargs)
 
 # Test that we can !include a file.
 export NIX_USER_CONF_FILES=$here/config/nix-with-bang-include.conf
-var=$(nix config show | grep '^experimental-features =' | cut -d '=' -f 2 | xargs)
-[[ $var == nix-command ]]
+var=$(nix config show | grep '^fsync-metadata =' | cut -d '=' -f 2 | xargs)
+[[ $var == true ]]
 
 # Test that it's possible to load config from the environment
 prev=$(nix config show | grep '^cores' | cut -d '=' -f 2 | xargs)

tests/functional/config/nix-with-bang-include.conf

@@ -1,2 +1,2 @@
-experimental-features = nix-command
+fsync-metadata = true
 !include ./missing-extra-config.conf

tests/functional/experimental-features.sh

@@ -79,12 +79,3 @@ nix --experimental-features '' --help 1>/dev/null
 nix --experimental-features '' doctor --help 1>/dev/null
 nix --experimental-features '' repl --help 1>/dev/null
 nix --experimental-features '' upgrade-nix --help 1>/dev/null
-
-# These 3 arguments are currently given to all commands, which is wrong (as not
-# all care). To deal with fixing later, we simply make them require the
-# nix-command experimental features --- it so happens that the commands we wish
-# stabilizing to do not need them anyways.
-for arg in '--print-build-logs' '--offline' '--refresh'; do
-    nix --experimental-features 'nix-command' "$arg" --help 1>/dev/null
-    expect 1 nix --experimental-features '' "$arg" --help 1>/dev/null
-done