spirv-val: Add Mesh Primitive Built-In validaiton

[spencer-lunarg]

for #4919

Adds the basic built-in VUs for

• PrimitivePointIndicesEXT
• PrimitiveLineIndicesEXT
• PrimitiveTriangleIndicesEXT

[pmistryNV]

@greg-lunarg just to confirm this commit still doesn't fix the bug #4919 .
It only adds validation support for the three builtins PrimitivePointIndicesEXT, PrimitiveLineIndicesEXT and PrimitiveTriangleIndicesEXT

[spencer-lunarg]

@pmistryNV this only added

    {spv::BuiltIn::PrimitivePointIndicesEXT,  {7041, 7043, 7044}},
    {spv::BuiltIn::PrimitiveLineIndicesEXT,   {7047, 7049, 7050}},
    {spv::BuiltIn::PrimitiveTriangleIndicesEXT, {7053, 7055, 7056}},

The remaining VUs still listed in #4919 (comment)

If you search the VU in the source code you can easily find if they are added or not