Update TestValidation/Duration_Validation_test_2

TestValidation/Duration_Validation_test_2 is broken. We should fix or remove.

```
=== RUN   TestValidation/Duration_Validation_test_2
    eval_test.go:346: Compile() got error = <nil>, wantErr true
    --- FAIL: TestValidation/Duration_Validation_test_2 (0.00s)
```