Full vector and fully specified vector swizzle stores are not affected by this change, only partial swizzles ie swizzles with fewer components than the vector being stored to.
Previously the vector being stored to loaded and any components not specified in the swizzle were used to create a full store to the vector.
While this change generates more SPIR-V instructions, it is necessary for correctness.
Fixes#2518.
Apart from allowing redeclaration of gl_MeshPerVertexNV and gl_MeshPerPrimitiveNV blocks, this change also -
- Resize clip/cull perview distances based on static index use
- Error out use of both single-view and per-view builtins
- Add new gtests with redeclared blocks and edit existing test output
- Fix couple of typos
