[clang] [llvm] [HLSL][RootSignature] Add parsing for empty RootConstants (PR #137999)

[via cfe-commits]

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@@ -252,6 +252,32 @@ TEST_F(ParseHLSLRootSignatureTest, ValidSamplerFlagsTest) {
   ASSERT_TRUE(Consumer->isSatisfied());
 }
 
+TEST_F(ParseHLSLRootSignatureTest, ValidParseRootConsantsTest) {
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joaosaffran wrote:

```suggestion
TEST_F(ParseHLSLRootSignatureTest, ValidParseRootConstantsTest) {
```

nit: Also, shouldn't this be, `ValidParseEmptyRootConstantsTest`, then we add more tests later on ?

https://github.com/llvm/llvm-project/pull/137999