Update tests

- remove tests that were creating files outside the test directory
- add tests with cycles longer than 1

test/blackbox-tests/test-cases/github764/run.t

@@ -1,6 +1,28 @@
-  $ mkdir -p c1 && cd c1 && ln -s . x && ln -s . y && jbuilder build
+  $ rm -rf x c* symlink*
+
+  $ mkdir -p c1
+  $ cd c1 && ln -s . x
+  $ cd c1 && ln -s . y
+  $ cd c1 && dune build
   Path . has already been scanned. Cannot scan it again through symlink x
   [1]
-  $ mkdir -p c2 && cd c2 && ln -s x ../../ && jbuilder build
-  $ mkdir -p c3 && cd c3 && ln -s x y && ln -s y x && jbuilder build
-  $ cd symlink-outside-root && ln -s ../sample-exe sample && jbuilder exec --root . -- sample/foo.exe
+
+  $ mkdir -p c2/{a,b}
+  $ cd c2 && ln -s ../b a/x
+  $ cd c2 && ln -s ../a b/x
+  $ cd c2 && dune build
+  Path a has already been scanned. Cannot scan it again through symlink a/x/x
+  [1]
+
+  $ mkdir symlink-outside-root
+  $ cd symlink-outside-root && ln -s ../sample-exe sample
+  $ cd symlink-outside-root && jbuilder exec --root . -- sample/foo.exe
+  foo
+
+  $ mkdir -p symlink-outside-root2/{root,other/{a,b}}
+  $ cd symlink-outside-root2 && ln -s ../b other/a/x
+  $ cd symlink-outside-root2 && ln -s ../a other/b/x
+  $ cd symlink-outside-root2 && ln -s ../other root/src
+  $ cd symlink-outside-root2/root && dune build
+  Path b has already been scanned. Cannot scan it again through symlink src/a/x/x/x
+  [1]