USM testing rework for better USM support

[RossBrunton]

Overview

This is a small rework of the USM testing framework to make it easier to add new USM memory types in the future, and also adds shared USM support to many tests.

Reason for change

USM shared memory testing was lacking, this improves it by adding USM testing to most tests that currently do both device and host tests. It also removes duplication in the test suite itself.

Description of change

This change brings a lot of duplicated code into
cl_intel_unified_shared_memory_Test (the base class of many tests). Specifically, it provides properties to check host and shared memory USM support, and helper functions to generate USM pointers.

One of the design changes was adding a way to iterate through all available USM pointer types without having to copy-paste code. This is used to add shared allocations to many places alongside device and host allocations.

This results in the tests doing more work, but this only causes a 10% reduction in the time taken for testing, which is about 300ms on my system.

Anything else we should know?

N/A

Checklist

• Read and follow the project Code of Conduct.
• Make sure the project builds successfully with your changes.
• Run relevant testing locally to avoid regressions.
• Run clang-format-16 (the most
  recent version available through pip) on all modified code.