Fix stories model export (#3622)

Summary:
Pull Request resolved: https://github.com/pytorch/executorch/pull/3622

## Context

WIth the amount of newly added operators, exporting the Stories model via the `export_llama` script is currently broken. This changeset mainly upgrades `VulkanPartitioner` to allow more fine grained control over which nodes are partitioned:

1. Update how operators are listed and allow specifying features for specific operators
2. Check node arguments and output to see that they are valid before marking them as supported.
3. Allow partitioning to select only operators that support dynamic shapes
ghstack-source-id: 226482740

Reviewed By: copyrightly, jorgep31415

Differential Revision: D57385871

fbshipit-source-id: 0ac6f3c1394541d2a5b3db9a443cca4b48dd89eb