Nested `insertvalue`

[michel2323]

In Julia, we send nested insertvalue through the Khronos SPIRV translator. This leads to OpCompositeInsert and hitting [this] (

intel-graphics-compiler/IGC/Compiler/CISACodeGen/MemOpt.cpp

Line 4947 in bd67908

IGC_ASSERT_MESSAGE(Indices.size() == 1, "ICE: nested struct not supported!");

).

Our workaround until this is supported is to flatten the insert JuliaGPU/oneAPI.jl#548 .