[llvm] [CGSCCPassManagerTest] Replace no-op bitcast to create constant using the old function (PR #72460)

[Nikita Popov via llvm-commits]

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@@ -1633,8 +1633,7 @@ TEST_F(CGSCCPassManagerTest, TestUpdateCGAndAnalysisManagerForPasses8) {
 
         // Create an unsused constant that is referencing the old (=replaced)
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nikic wrote:

```suggestion
        // Create an unused constant that is referencing the old (=replaced)
```
Fix this typo while you're here?

https://github.com/llvm/llvm-project/pull/72460