Add a whitelist for the values being passed into OpDecoration and OpMemberDecoration, for the WebGPU env from the draft spec:

Only the following decorations are valid:

• SpecId
• Block
• RowMajor
• ColMajor
• ArrayStride (also see "Layouts" below)
• MatrixStride (also see "Layouts" below)
• Builtin (also see "Built-In Variables" below)
• NoPerspective, only in the Input storage class and the Fragment execution model
• Flat, only in the Input storage class and the Fragment execution model
• Centroid
• Restrict
• Aliased
• NonWritable
• NonReadable
• Uniform
• Location, required for all Input and Output, see "Interface" section below
• Component
• Index
• Binding
• DescriptorSet
• Offset (also see "Layouts" below)
• NoContraction