patch 9.1.0419: eval.c not sufficiently tested

Problem:  eval.c not sufficiently tested
Solution: Add a few more additional tests for eval.c,
          (Yegappan Lakshmanan)

closes: #14799

Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_vim9_expr.vim

@@ -2118,6 +2118,12 @@ def Test_expr9_number()
       Test()
   END
   v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+    eval("10\n")
+  END
+  v9.CheckSourceScriptFailure(lines, "E488: Trailing characters: \n")
 enddef
 
 def Test_expr9_float()