[llvm] [Utils][SPIR-V] Adding spirv-sim to LLVM (PR #107094)

[Nathan Gauër via llvm-commits]

Keenuts wrote:

@joker-eph 
I opened an RFC (https://discourse.llvm.org/t/rfc-spir-v-simulator/81168)

Additional node: do keep in mind that this is an additional tool to what we have today.
Today we already use `FileCheck` and `spirv-val` for the SPIR-V backend. This just come in addition to all that, to test cases for which `FileCheck` has IMO strong limits.
The goal is not to rely only on `spirv-sim` to test the SPIR-V backend.

https://github.com/llvm/llvm-project/pull/107094