Add new acceptance test scenario (019)

```
  Error:
    × Main thread panicked.
    ├─▶ at crates/lang/src/uplc.rs:2001:81
    ╰─▶ called `Option::unwrap()` on a `None` value
  ```

examples/acceptance_tests/019/aiken.toml

@@ -0,0 +1,2 @@
+name = "acceptance_test_019"
+version = "0.0.0"

examples/acceptance_tests/019/lib/test.ak

@@ -0,0 +1,14 @@
+pub fn map(opt: Option<a>, f: fn(a) -> result) -> Option<result> {
+  when opt is {
+    None -> None
+    Some(a) -> Some(f(a))
+  }
+}
+
+test map_1() {
+  map(None, fn(_) { 14 }) == None
+}
+
+test map_2() {
+  map(None, fn(_) { Nil }) == None
+}