[clang] [HLSL] Add the `Frs` `DXC` driver option (PR #157690)

[Finn Plummer via cfe-commits]

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@@ -524,6 +530,7 @@ bool HLSLToolChain::requiresBinaryTranslation(DerivedArgList &Args) const {
 bool HLSLToolChain::requiresObjcopy(DerivedArgList &Args) const {
   return Args.hasArg(options::OPT_dxc_Fo) &&
          (Args.hasArg(options::OPT_dxc_strip_rootsignature) ||
+          Args.hasArg(options::OPT_dxc_Frs) ||
           isRootSignatureTarget(Args));
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inbelic wrote:

```suggestion
          Args.hasArg(options::OPT_dxc_Frs) || isRootSignatureTarget(Args));
```

https://github.com/llvm/llvm-project/pull/157690