[HLSL] Write tests for space inside register annotation

[bob80905]

Register annotations register(u0, space1), may involve an optional space parameter. This parameter should be tested for when it may be invalid (for example, non-numeric suffixes, being placed as the first argument, etc)

[bob80905]

clang\test\SemaHLSL\resource_binding_attr_error.hlsl already has sufficient testing coverage for the space parameter. Closing because this isn't an issue.

[damyanp]

I don't see any tests in that file to validate that an error is generated if you try and set a register space on a global.