Large RenderThread cost when using r.ShaderCompiler.JobCacheDDC

In the editor when running with ODSC our shader maps will never be complete.
This causes us to continually evaluate uniform expressions every frame for every material.
This results in a large RT cost. The culprit code is the following:

FMaterialRenderProxy::EvaluateUniformExpressions:

`OutUniformExpressionCache.bUpToDate = Context.Material.IsRenderingThreadShaderMapComplete();`

Is it safe to just assuming the cache is up to date? and as long as we re-cache everytime we get a new shader map things should always be up to date.

[Link Removed]

1. Change shaders
2. Launch PIE
3. Look at Unreal Insights captures
4. See large cost in FMaterialRenderProxy::EvaluateUniformExpressions