test: fix utop tests

Signed-off-by: Rudi Grinberg <[email protected]>

<!-- ps-id: ad13c693-c903-495c-9b2c-3c8cf6212119 -->

Signed-off-by: Rudi Grinberg <[email protected]>

Author: rgrinberg

test/blackbox-tests/test-cases/utop/utop-default/lib-in-root.t/run.t

@@ -1,7 +1,5 @@
 By default, dune utop tries to make a toplevel for the current directory:
 
-  $ echo 'exit 0;;' | dune utop . -- -init "" | grep -v 'version'
-  Enter #help;; for help.
-  
-  Init file not found: "".
-  # 
+  $ touch empty
+  $ echo 'print_endline "success";; exit 0;;' | dune utop . -- -stdin -init empty
+  success

test/blackbox-tests/test-cases/utop/utop-default/nothing-in-root.t/run.t

@@ -1,10 +1,8 @@
 Utop will load libs recursively:
 
-  $ echo 'exit 0;;' | dune utop . -- -init "" | grep -v 'version'
-  Enter #help;; for help.
-  
-  Init file not found: "".
-  # 
+  $ touch empty
+  $ echo 'print_endline "success";; exit 0;;' | dune utop . -- -stdin -init empty
+  success
 
 
 The message where the library path does not exist is different: