[Process/NetBSD] Copy changes from FreeBSDRemote and reformat

Copy changes, including:

- NativeProcessNetBSD::GetLoadedModuleFileSpec()
  and NativeProcessNetBSD::GetFileLoadAddress() methods

- split x86 register sets by CPU extensions

- use offset/size-based register reading/writing

Differential Revision: https://reviews.llvm.org/D93541

lldb/test/API/python_api/lldbutil/iter/TestRegistersIterator.py

@@ -23,7 +23,6 @@ class RegistersIteratorTestCase(TestBase):
             'main.cpp', '// Set break point at this line.')
 
     @add_test_categories(['pyapi'])
-    @expectedFailureNetBSD
     def test_iter_registers(self):
         """Test iterator works correctly for lldbutil.iter_registers()."""
         self.build()