ScalarizeVecAndMatConstructorArgs on WGSL shaders. WGSL does not support mixing types in the constructors of vectors and matrices. Use the ScalarizeVecAndMatConstructorArgs traverser to scalarize these constructors and update it to cast to the destination type if the inputs are not in that type already. Bug: angleproject:395659799 Change-Id: I4c270f2b18e79393e3c187916f33ad719bc88a63 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6427067 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Geoff Lang <geofflang@chromium.org>