Put functional tests in `tests/functional`

I think it is bad for these reasons when `tests/` contains a mix of
functional and integration tests

 - Concepts is harder to understand, the documentation makes a good
   unit vs functional vs integration distinction, but when the
   integration tests are just two subdirs within `tests/` this is not
   clear.

 - Source filtering in the `flake.nix` is more complex. We need to
   filter out some of the dirs from `tests/`, rather than simply pick
   the dirs we want and take all of them. This is a good sign the
   structure of what we are trying to do is not matching the structure
   of the files.

With this change we have a clean:
```shell-session
$ git show 'HEAD:tests'
tree HEAD:tests

functional/
installer/
nixos/
```

(cherry picked from commit 68c81c737571794f7246db53fb4774e94fcf4b7e)

1 files changed, 0 insertions, 56 deletions

diff --git a/tests/nar-access.sh b/tests/nar-access.sh
deleted file mode 100644
index d487d58d2..000000000
--- a/tests/nar-access.sh
+++ /dev/null
@@ -1,56 +0,0 @@
-source common.sh
-
-echo "building test path"
-storePath="$(nix-build nar-access.nix -A a --no-out-link)"
-
-cd "$TEST_ROOT"
-
-# Dump path to nar.
-narFile="$TEST_ROOT/path.nar"
-nix-store --dump $storePath > $narFile
-
-# Check that find and nar ls match.
-( cd $storePath; find . | sort ) > files.find
-nix nar ls -R -d $narFile "" | sort > files.ls-nar
-diff -u files.find files.ls-nar
-
-# Check that file contents of data match.
-nix nar cat $narFile /foo/data > data.cat-nar
-diff -u data.cat-nar $storePath/foo/data
-
-# Check that file contents of baz match.
-nix nar cat $narFile /foo/baz > baz.cat-nar
-diff -u baz.cat-nar $storePath/foo/baz
-
-nix store cat $storePath/foo/baz > baz.cat-nar
-diff -u baz.cat-nar $storePath/foo/baz
-
-# Test --json.
-diff -u \
-    <(nix nar ls --json $narFile / | jq -S) \
-    <(echo '{"type":"directory","entries":{"foo":{},"foo-x":{},"qux":{},"zyx":{}}}' | jq -S)
-diff -u \
-    <(nix nar ls --json -R $narFile /foo | jq -S) \
-    <(echo '{"type":"directory","entries":{"bar":{"type":"regular","size":0,"narOffset":368},"baz":{"type":"regular","size":0,"narOffset":552},"data":{"type":"regular","size":58,"narOffset":736}}}' | jq -S)
-diff -u \
-    <(nix nar ls --json -R $narFile /foo/bar | jq -S) \
-    <(echo '{"type":"regular","size":0,"narOffset":368}' | jq -S)
-diff -u \
-    <(nix store ls --json $storePath | jq -S) \
-    <(echo '{"type":"directory","entries":{"foo":{},"foo-x":{},"qux":{},"zyx":{}}}' | jq -S)
-diff -u \
-    <(nix store ls --json -R $storePath/foo | jq -S) \
-    <(echo '{"type":"directory","entries":{"bar":{"type":"regular","size":0},"baz":{"type":"regular","size":0},"data":{"type":"regular","size":58}}}' | jq -S)
-diff -u \
-    <(nix store ls --json -R $storePath/foo/bar| jq -S) \
-    <(echo '{"type":"regular","size":0}' | jq -S)
-
-# Test missing files.
-expect 1 nix store ls --json -R $storePath/xyzzy 2>&1 | grep 'does not exist in NAR'
-expect 1 nix store ls $storePath/xyzzy 2>&1 | grep 'does not exist'
-
-# Test failure to dump.
-if nix-store --dump $storePath >/dev/full ; then
-    echo "dumping to /dev/full should fail"
-    exit -1
-fi