4ba61f5a30
Start plumbing through support for the `SPV_KHR_cooperative_matrix` extension: https://github.com/KhronosGroup/SPIRV-Registry/blob/master/extensions/KHR/SPV_KHR_cooperative_matrix.html. Register the extension, add new coop matrix type, and add `spirv.KHR.CooperativeMatrixLength` op to exercise it. Make sure that mixing of the KHR and NV coop matrix extensions is not allowed. Make cast verification more robust. Reviewed By: antiagainst, qedawkins Differential Revision: https://reviews.llvm.org/D154877