Check for clean repo after tests (#11409)

Goal: detect problems like adressed by #11407 or missing `Cargo.lock`
update early

Try to fail when there is a non clear `git status` message

scripts/test_virtualenv.nu

@@ -53,4 +53,5 @@ def main [] {
         let msg = $"OUTPUT:\n($o)\n\nEXPECTED:\n($e)"
         error make {msg: $"Output does not match the expected value:\n($msg)"}
     }
+    rm script.nu
 }