[HLSL] Add appropriate validation for MD_range metadata kind

[bob80905]

The MD_range metadata kind needs better validation, so that it mimics the validation in DXC.
Currently, all MD_range metadata node kinds are accepted. However, there needs to be further checks, like in DXC.
For example, in DXC, Verifier.cpp has a function, visitRangeMetadata that validates the range metadata node kind. One check, among many, is that the number of operands must be even. This needs to be validated to allow this metadata type in the whitelist.