Re: [PATCH v10 0/1] MR673: tests/shader-runner: Add sampler comparison tests.

[Henri Verbeet (＠hverbeet)]

Could we use a shader like this (untested) instead?:
```hlsl
Texture2D<float> t : register(t0);
SamplerComparisonState s : register(s0);

float ref, delta;

float4 main() : sv_target
{
    return float4(
        t.SampleCmpLevelZero(s, float2(0.5, 0.5), ref - delta),
        t.SampleCmpLevelZero(s, float2(0.5, 0.5), ref),
        t.SampleCmpLevelZero(s, float2(0.5, 0.5), ref + delta),
        1.0);
}
```

This would allow testing three values in a single draw. Testing two values like the tests currently do isn't necessarily sufficient to distinguish the different comparison functions. For example, the current "less equal" results are indistinguishable from the "equal" results.