[llvm] [SPIRV] Print split 64-bit OpSwitch operands as a single operand for text output (PR #164886)

[Juan Manuel Martinez Caamaño via llvm-commits]

https://github.com/jmmartinez approved this pull request.

Looks good to me, but please wait for a second reviewer's approval since I'm fairly new to SPIRV.

https://github.com/llvm/llvm-project/pull/164886