[BUG] default property assignment must appear before child components

[nachumg]

• [x ] I have reviewed this project's contribution guidelines

Describe the bug
Specification Reference: Section 5.1.3.2 ("Assigning default values") allows a default property assignment to appear anywhere in a scope, and it should apply down-hierarchy to all component instances in that scope.

Tests show that systemrdl requires the default assignment to appear before any child components in the scope.

1. Add at bottom of https://github.com/SystemRDL/systemrdl-compiler/blob/main/test/test_intr_prop.py

        self.assertEqual(top.find_by_path("block_a_int.crc_error").get_property("hw"),                                                                                                                                                  
                         rdlt.AccessType.w)

2. Test passes.
3. Modify https://github.com/SystemRDL/systemrdl-compiler/blob/main/test/rdl_src/intr_prop.rdl
   • Move line 9 to after line 16
4. Test fails.