[JIT] Enable @ignore and @unused syntax for ignoring properties

**Summary**
This commit enables `@ignore` and `@unused` syntax for ignoring
properties, but works only if these decorators are applied to a function
before the @Property decorator. Despite this, ignoring properties is
more intuitive with this feature enabled.

**Test Plan**
This commit updates the existing unit tests for class type and module
properties to test properties ignored using `@ignore` and `@unused`.
Summary:

Test Plan:

Reviewers:

Subscribers:

Tasks:

Tags:

ghstack-source-id: 7a545729ca5efff280658a00e32e5053d7619f9d
Pull Request resolved: #45261

test/jit/test_class_type.py

@@ -1180,6 +1180,15 @@ def attr(self) -> int:
             def unsupported(self) -> int:
                 return sum([self.a])
 
+            @property
+            @torch.jit.unused
+            def unsupported_2(self) -> int:
+                return sum([self.a])
+
+            @unsupported_2.setter
+            def unsupported_2(self, value):
+                self.a = sum([self.a])
+
             @attr.setter
             def attr(self, value: int):
                 self.a = value + 3

test/test_jit_py3.py

@@ -639,6 +639,15 @@ def attr(self):
             def ignored_attr(self):
                 return sum([self.a])
 
+            @property
+            @torch.jit.unused
+            def ignored_attr_2(self):
+                return sum([self.a])
+
+            @ignored_attr_2.setter
+            def ignored_attr_2(self, value):
+                self.a = sum([self.a])
+
             @attr.setter
             def attr(self, a: int):
                 if a > 0:

torch/jit/frontend.py

@@ -16,7 +16,7 @@
 )
 from torch._utils_internal import get_source_lines_and_file
 
-from torch._jit_internal import SourceContext, should_drop, is_static_fn
+from torch._jit_internal import SourceContext, should_drop, is_static_fn, is_ignored_fn
 import torch.jit.annotations
 
 # Borrowed from cPython implementation
@@ -147,7 +147,7 @@ def get_class_properties(cls, self_name):
     # Create Property TreeView objects from inspected property objects.
     properties = []
     for prop in props:
-        if prop[0] not in ignored_properties:
+        if prop[0] not in ignored_properties and not is_ignored_fn(prop[1].fget):
             getter = get_jit_def(prop[1].fget, f"__{prop[0]}_getter", self_name=self_name)
             setter = get_jit_def(prop[1].fset, f"__{prop[0]}_setter", self_name=self_name) if prop[1].fset else None
             properties.append(Property(getter.range(), Ident(getter.range(), prop[0]), getter, setter))