[clang] [HLSL][Driver] Make vk1.3 the default. (PR #143384)

[Nathan Gauër via cfe-commits]

================
@@ -1596,28 +1596,26 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
       A->claim();
 
       if (Args.hasArg(options::OPT_spirv)) {
+        const llvm::StringMap<llvm::Triple::SubArchType> ValidTargets = {
+            {"vulkan1.2", llvm::Triple::SPIRVSubArch_v15},
+            {"vulkan1.3", llvm::Triple::SPIRVSubArch_v16}};
         llvm::Triple T(TargetTriple);
-        T.setArch(llvm::Triple::spirv);
-        T.setOS(llvm::Triple::Vulkan);
 
-        // Set specific Vulkan version if applicable.
+        // Set specific Vulkan version. Default to vulkan1.3.
+        auto TargetInfo = ValidTargets.find("vulkan1.3");
----------------
Keenuts wrote:

```suggestion
        auto TargetInfo = ValidTargets.find("vulkan1.3");
        assert(TargetInfo != ValidTargets.end());
```

https://github.com/llvm/llvm-project/pull/143384