[CLEANUP] Clean up existing structural tests when structural testing infrastructure is created

[denise-k]

Recently, there have been some discussions around creating infrastructure for structural tests, which test for the structure of the generated code rather than correctness of the output. This is currently on the backlog. Once the infrastructure is in place, there are places where structural tests exist in the code already which should be refactored to be more readable/cleaner.

Here's an initial list (to be edited over time):

• In tests/python/relay/aot/test_crt_aot.py: test_aot_codegen_backend_alloc_workspace_calls (per Move the allocates of AoT codegen to be TVMBAWs #9065)

[areusch]

In particular it would be great to create test-utils which allow someone to traverse TIR and find nodes e.g. similar to XPath so that it's easy to assert that a pass adds/removes various attrs from all instances of a particular node type.