Add new acceptance test scenario: 059

```
  Error:
    × Main thread panicked.
    ├─▶ at crates/aiken-lang/src/uplc.rs:1451:52
    ╰─▶ called `Option::unwrap()` on a `None` value
  ```

  See also: #310

examples/acceptance_tests/059/aiken.lock

@@ -0,0 +1,5 @@
+# This file was generated by Aiken
+# You typically do not need to edit this file
+
+requirements = []
+packages = []

examples/acceptance_tests/059/aiken.toml

@@ -0,0 +1,2 @@
+name = "aiken-lang/acceptance_test_059"
+version = "0.0.0"

examples/acceptance_tests/059/lib/tests.ak

@@ -0,0 +1,7 @@
+test foo() {
+  let xs = [[1, 2], [4, 5]]
+  when xs is {
+    [[_, _], [_, _]] -> True
+    _ -> False
+  }
+}