DOTS compatible error/loading shaders GFXHYR-308

[vincent-breysse]

/!\ Most of the changes are test related

Purpose of this PR

URP changes only

• Merge FallbackError.shader and MaterialError.shader. These shaders were originally split to have a DOTS compatible error shader while still having a shader being compatible with built-in RP.
  However this PR tries to simplify this by having only one shader with two sub shaders and use the Tags { "RenderPipeline" = "UniversalPipeline" } thingy

URP/HDRP changes

• Add #pragma editor_sync_compilation to error/loading shaders to avoid the "error/loading shader is currently loading" edge case
• Add DOTS compatible loading shader
• Some [Reload("Path/To/Shader.shader")] additions/updates

These new shaders are needed by Hybrid Renderer since built-in error/loading shaders aren't DOTS compatible.

Testing status

- Manual testing

- URP/HDRP QA pass

- Added URP/HDRP scenes to test various error shader cases when rendering with a BRG (not automated) :

- Compilation error in HLSL code
- Compilation error in shader parser (different internal handling than an error in HLSL code)
- Shader with missing DOTS_INSTANCING_ON keyword
- Material with missing shader
- MeshRenderer with missing material
- MeshRenderer with null material
- Shader non SRP Batcher compatible
- Shader not supported
- Shader pass not supported (different internal handling than whole shader not being supported)

- Yamato PR URP/HDRP on trunk green except:

Failing on master as well:
- URP_Lighting on Win_Vulkan_Standalone_mono_Linear on version trunk
- HDRP on Win_DX11_playmode_mono_Linear on version trunk
- HDRP on Win_DX11_playmode_XR_mono_Linear on version trunk
- HDRP on Win_DX12_playmode_mono_Linear on version trunk
- HDRP on Win_Vulkan_playmode_mono_Linear on version trunk
- HDRP on OSX_Metal_playmode_mono_Linear on version trunk
- HDRP on Linux_Vulkan_playmode_mono_Linear on version trunk
- HDRP_DXR on Win_DX12_playmode_mono_Linear on version trunk

[github-actions]

Hi! This comment will help you figure out which jobs to run before merging your PR. The suggestions are dynamic based on what files you have changed.
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Search for your PR branch using the search bar at the top, then add the following segment(s) to the end of the URL (you may need multiple tabs depending on how many packages you change)

HDRP
/jobDefinition/.yamato%2Fall-hdrp.yml%23PR_HDRP_trunk
With changes to HDRP packages, you should also run
/jobDefinition/.yamato%2Fall-lightmapping.yml%23PR_Lightmapping_trunk

URP
/jobDefinition/.yamato%252Fall-urp.yml%2523PR_URP_trunk
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/jobDefinition/.yamato%2Fall-lightmapping.yml%23PR_Lightmapping_trunk

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[sebastienlagarde]

small comment otherwise good for hdrp section

[TomasKiniulis]

Tested BatchRendererGroup_HDRP, Amalienborg palace builds on Deferred and Forward with Game Objects and BRG. Looks good on HDRP side.

Test doc for more details: https://confluence.unity3d.com/pages/viewpage.action?pageId=172268208

[cinight]

All good. Test Doc: https://docs.google.com/document/d/1QAfxaWR3YDvCPR6pbvTniqassj1ETHdD-j94cfoUCVs/edit#

[phi-lira]

LGTM.