[WIP] Implement subroutine opcodes

Author: Peppece

tests/core/opcodes/test_opcodes.py

@@ -1159,7 +1159,7 @@ def test_jumpsub(vm_class, code, expect_gas_used):
     assert comp.get_gas_used() == expect_gas_used
 
 
-@pytest.mark.xfail(reason="invalid subroutines")  # noqa: F811
+@pytest.mark.xfail(reason="invalid subroutines")
 @pytest.mark.parametrize(
     'vm_class, code',
     (
@@ -1177,7 +1177,7 @@ def test_jumpsub(vm_class, code, expect_gas_used):
         ),
     )
 )
-def test_jumpsub(vm_class, code):
+def test_failing_jumpsub(vm_class, code):
     computation = setup_computation(vm_class, CANONICAL_ADDRESS_B, decode_hex(code))
     comp = computation.apply_message(
         computation.state,