Add repro for gh10232 (#10233)

Signed-off-by: Stephen Sherratt <stephen@sherra.tt>

test/blackbox-tests/test-cases/pkg/pin-stanza/update-non-dune-local-pin.t

@@ -0,0 +1,67 @@
+This demonstrates an issue when pinning a non-opam package. After attempting to
+build the package, changes to the package are only picked up by dune after
+running `dune clean`, even if building the package failed.
+
+  $ . ../helpers.sh
+
+  $ mkrepo
+  $ add_mock_repo_if_needed
+
+  $ cat >dune-project <<EOF
+  > (lang dune 3.13)
+  > (pin
+  >  (url "file://$PWD/foo")
+  >  (package (name foo)))
+  > (package
+  >  (name main)
+  >  (depends foo))
+  > EOF
+
+Make a package "foo" whose build will fail after printing a message:
+  $ mkdir foo
+  $ cat >foo/foo.opam <<EOF
+  > opam-version: "2.0"
+  > build: [
+  >  [ make ]
+  > ]
+  > EOF
+  $ cat >foo/Makefile <<EOF
+  > all:
+  > 	echo aaa
+  > 	false
+  > EOF
+
+  $ dune pkg lock
+  Solution for dune.lock:
+  - foo.dev
+
+Attempt to build the packgage the first time:
+(the error from make is grep'd out because it is not consistant across different systems)
+  $ dune build 2>&1 | grep -v make
+  echo aaa
+  aaa
+  false
+  -> required by _build/_private/default/.pkg/foo/target/cookie
+
+Update the message that gets printed while building foo:
+  $ cat >foo/Makefile <<EOF
+  > all:
+  > 	echo bbb
+  > 	false
+  > EOF
+
+The change to the package is ignored:
+  $ dune build 2>&1 | grep -v make
+  echo aaa
+  aaa
+  false
+  -> required by _build/_private/default/.pkg/foo/target/cookie
+
+  $ dune clean
+
+The change to the package is picked up now that we've run `dune clean`:
+  $ dune build 2>&1 | grep -v make
+  echo bbb
+  bbb
+  false
+  -> required by _build/_private/default/.pkg/foo/target/cookie