Minor cleanup of wrapper tests, preventing their presence unless the library is available.
#jira UE-202105
#rb rod.bogart, Ruslan.Idrisov
[CL 30192162 by eric renaudhoude in ue5-main branch]
- move sequence of preprocessing steps out of ShaderPreprocessor module and into UE::ShaderCompilerCommon::ExecuteShaderPreprocessingSteps; the former is now explicitly just the low-level preprocessor lib
- add an implementation of PreprocessShader in FBaseShaderFormat so backends which have no custom code to execute as part of preprocessing can just automatically inherit this implementation, and fix up such backends to eliminate now-unnecessary overrides
#rb christopher.waters, Laura.Hermanns
[CL 30178136 by dan elksnitis in ue5-main branch]
Now `Automation.EnableStereoTestVariants=1` (off by default) enables ViewRectOffset, and adding `Automation.LightweightStereoTestVariants=1` causes us to ONLY run ViewRectOffset (on by default).
#jira UE-194361
#rb Jerome.Delattre
[CL 30174576 by christopher fiala in ue5-main branch]
- never append the environment defines as commented code to the source used for further preprocessing/compilation; instead only append it to the debug USF
- strip comments after loading the debug usf in direct compile mode as some backends expect comments to have already been removed and the extra ones we add to the debug dump cause them to barf
- change all #if 0s in the debug usf to block comments instead so the above can strip them (said backends also don't like preprocessor directives left in the file)
#rb Jason.Nadro, rob.krajcarski
[CL 30161438 by dan elksnitis in ue5-main branch]
- Timing View: Fixed fill color for graph series.
- Timing View: Increased tickness of lines for graph series based on scale factor and enabled antialias.
#rb Catalin.Dragoiu
[CL 30149654 by ionut matasaru in ue5-main branch]
