patch 8.2.1890: Vim9: strange error for subtracting from a list

Problem:    Vim9: strange error for subtracting from a list.
Solution:   Check getting a number, not a string. (closes #7167)
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index 9b5b4ff..568c3bf 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1128,7 +1128,19 @@
       vim9script
       echo {} - 22
   END
-  CheckScriptFailure(lines, 'E731:', 2)
+  CheckScriptFailure(lines, 'E728:', 2)
+
+  lines =<< trim END
+      vim9script
+      echo [] - 33
+  END
+  CheckScriptFailure(lines, 'E745:', 2)
+
+  lines =<< trim END
+      vim9script
+      echo 0z1234 - 44
+  END
+  CheckScriptFailure(lines, 'E974:', 2)
 
   lines =<< trim END
       vim9script