Update on "Add preserve_ops to EdgeCompileConfig"

1. Add `preserve_ops` to `EdgeCompileConfig`
2. Remove preserved ops from the decomposition table in `to_edge`.
3. Add checks to the verifier ensuring that preserved ops do not have mutations or views.
4. Update 'core_aten_exception_list' to be 'preserved_ops' in `to_edge_transform_and_lower`.

Context/Usage
**core_aten_ops_exception_list**
- Contains operators that are missing a decomposition to core aten.
- Exclude these so that verification can still be run on the rest of the graph.
- Ideally, this list should be empty.

**preserve_ops**
- Contains operators that the user specifically does not want decomposed.
- Must be aten; custom ops are ignored by verifier.

Edge case:
- If an aten operator does not have a decomp, and the user specifically wants it to be preserved, put it in preserve_ops rather than core_aten_ops_exception_list.

Differential Revision: [D78298749](https://our.internmc.facebook.com/intern/diff/D78298749/)

[ghstack-poisoned]

Author: lucylq

backends/nxp/nxp_backend.py

@@ -174,7 +174,7 @@ def preprocess(
             # Otherwise, we get violation that this op is not part of ATen Core ops.
             edge_program._verifiers = [
                 EXIREdgeDialectVerifier(
-                    class_only=True, exception_list=[torch.ops.aten.max_pool2d.default]
+                    class_only=True, core_aten_ops_exception_list=[torch.ops.aten.max_pool2d.default]
                 )
             ]
 

exir/verification/verifier.py

@@ -3,6 +3,8 @@
 #
 # This source code is licensed under the BSD-style license found in the
 # LICENSE file in the root directory of this source tree.
+#
+# pyre-unsafe
 
 import itertools
 import logging