[clang] [HLSL] Mark vector and matrix constructor-turned-InitListExprs as ListInitializations (PR #192151)

[Alex Sepkowski via cfe-commits]

https://github.com/alsepkow commented:

LGTUS: @bob80905 and I. One small comment where we weren't sure if an additional test case is valid to add.

https://github.com/llvm/llvm-project/pull/192151