[llvm] [SPIRV] Start adding support for `int128` (PR #170798)

[Vladimir Vereschaka via llvm-commits]

vvereschaka wrote:

Hi @AlexVlx ,

https://lab.llvm.org/buildbot/#/builders/187/builds/14435
there are failed tests on the expensive test builder, looks like because of this PR

```
# executed command: not /home/buildbot/worker/as-builder-4/ramdisk/expensive-checks/build/bin/llc -O0 -mtriple=spirv64-unknown-unknown /home/buildbot/worker/as-builder-4/ramdisk/expensive-checks/llvm-project/llvm/test/CodeGen/SPIRV/extensions/SPV_ALTERA_arbitrary_precision_integers/i128-addsub.ll -o /home/buildbot/worker/as-builder-4/ramdisk/expensive-checks/build/test/CodeGen/SPIRV/extensions/SPV_ALTERA_arbitrary_precision_integers/Output/i128-addsub.ll.tmp.spvt
# executed command: /home/buildbot/worker/as-builder-4/ramdisk/expensive-checks/build/bin/FileCheck /home/buildbot/worker/as-builder-4/ramdisk/expensive-checks/llvm-project/llvm/test/CodeGen/SPIRV/extensions/SPV_ALTERA_arbitrary_precision_integers/i128-addsub.ll --check-prefix=CHECK-ERROR
# .---command stderr------------
# | /home/buildbot/worker/as-builder-4/ramdisk/expensive-checks/llvm-project/llvm/test/CodeGen/SPIRV/extensions/SPV_ALTERA_arbitrary_precision_integers/i128-addsub.ll:6:16: error: CHECK-ERROR: expected string not found in input
# | ; CHECK-ERROR: LLVM ERROR: OpTypeInt type with a width other than 8, 16, 32 or 64 bits requires the following SPIR-V extension: SPV_ALTERA_arbitrary_precision_integers
# |                ^
# | <stdin>:1:1: note: scanning from here
# | 
...
```

would yo take care of it?

https://github.com/llvm/llvm-project/pull/170798