[Intel-gfx] [PATCH i-g-t] tests/i915/gem_ctx_switch: Update with engine discovery

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-06-27 11:20:19)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> I converted this one as an example, or at least to drive the discussion,
> how more complex tests can be converted.
> 
> I have kept the legacy execbuf abi testing prefixed with "legacy-".
> 
> New tests were added to exercise physical engines via engine discovery and
> also "all" tests have been updated in the same way.
> 
> To keep things simpler and avoid having to create separate contexts legacy
> tests have to be first since the __for_each_physical_engine iterator would
> otherwise configure the default context and confuse the test.
> 
> So legacy tests run on the unconfigured (with engine map) context and use
> a new helper gem_eb_flags_to_engine to look up the engine from the
> intel_execution_engines2 static list. This is only to enable the core test
> code to be shared.

Note that this misses the I915_EXEC_DEFAULT slot. That a rather
significant oversight.
-Chris