[GLTF] Validation Tests

[CedricGuillemet]

BabylonJS list of validation tests here : https://github.com/BabylonJS/Babylon.js/blob/master/tests/validation/config.json

• [x] GLTF Normals
• [x] GLTF Animation Node
• [x] GLTF Animation Node Misc
• [x] GLTF Animation Skin (0)
• [x] GLTF Animation Skin (1)
• [x] GLTF Animation Skin Type
• [x] GLTF Buffer Interleaved
• [x] GLTF Material
• [x] GLTF Material Alpha Blend
• [x] GLTF Material Alpha Mask
• [x] GLTF Material Double Sided (Front)
• [x] GLTF Material Double Sided (Back)
• [x] GLTF Material Metallic Roughness (0)
• [x] GLTF Material Metallic Roughness (1)
• [x] GLTF Material Mixed
• [x] GLTF Material Specular Glossiness (0)
• [x] GLTF Material Specular Glossiness (1)
• [x] GLTF Mesh Primitive Attribute
• [x] GLTF Mesh Primitive Mode (0)
• [x] GLTF Mesh Primitive Mode (1)
• [x] GLTF Mesh Primitive Vertex Color
• [x] GLTF Mesh Primitives
• [x] GLTF Mesh Primitives UV (0)
• [x] GLTF Mesh Primitives UV (1)
• [x] GLTF Node Attribute (0)
• [x] GLTF Node Attribute (1)
• [x] GLTF Node NegativeScale (0)
• [x] GLTF Node NegativeScale (1)
• [x] GLTF Texture Sampler (0)
• [x] GLTF Texture Sampler (1)
• [x] GLTF Sheen
• [x] GLTF ClearCoat
• [x] GLTF Alpha Blend
• [ ] GLTF Buggy with Draco Mesh Compression
• [ ] GLTF Buggy with Meshopt Compression
• [x] GLTF BoomBox with Unlit Material
• [x] GLTF Extension KHR_texture_transform
• [ ] GLTF Extension KHR_materials_volume
• [x] GLTF Extension KHR_materials_volume with attenuation
• [x] GLTF Extension KHR_materials_specular
• [x] GLTF Texture Linear Interpolation Test
• [ ] GLTF Mesh Primitive Attribute Test
• [x] GLTF Extension EXT_mesh_gpu_instancing
• [x] GLTF Extension KHR_materials_variants
• [x] GLTF ext MSFT_LOD
• [x] Iridescence - [ ] GLTF Serializer with Negative World Matrix - [ ] GLTF Serializer with Negative World Matrix (Right Handed) - [ ] GLTF Serializer Skinning and Animation - [ ] GLTF Serializer Skinning and Animation (Right Handed) - [ ] GLTF Serializer Morph Target Animation - [ ] GLTF Serializer Morph Target Animation Group - [ ] GLTF Serializer KHR materials clearcoat

[CedricGuillemet]

4 tests added with this PR : https://github.com/BabylonJS/BabylonNative/pull/812

[CedricGuillemet]

4 more : https://github.com/BabylonJS/BabylonNative/pull/815

[CedricGuillemet]

5 more with #1231

[CedricGuillemet]

2 more tests with https://github.com/BabylonJS/BabylonNative/pull/1344