This CL changes the id/name output from the validator to always use a
consistent id[%name] style. This removes the need for getIdOrName. The
name lookup is changed to use the NameMapper so the output is consistent
with what the disassembler will produce.
Fixes#2137
* Check rules from Execution Mode tables, 2.16.2 and the Vulkan
environment spec
* Allows MeshNV execution model with the following execution modes
* LocalSize, LocalSizeId, OutputPoints and OutputVertices
* Done to not break their validation
OpPhi instruction must appear before all non-OpPhi instructions
except for OpLine. Without this commit, Validator does not check
the case that an OpPhi is preceeded by an OpLine and the OpLine is
preceeded by a non-OpPhi instruction that is not OpLine.
