* Use IREE tf tools to save .mlir modules when generating shark_tank.
* Add option to pytest for enabling auto-updates to local shark tank.
* xfail mobilenet torch on cpu, cuda and fix CI macos setup
* Update test-models.yml to disable macos vulkan CI.
* adds support to default to tuned model
currently setup for tf bert/resnet50
going to refactor test class to avoid having to
add an argument to 50+ files
* adds an option to avoid installing iree
useful when building iree from source
specify env variable NO_BACKEND=1
