Update src/tests/JIT/Regression/JitBlue/Runtime_115532/Runtime_115532.cs

Co-authored-by: Filip Navara <[email protected]>

Author: tannergooding

src/tests/JIT/Regression/JitBlue/Runtime_115532/Runtime_115532.cs

@@ -3,6 +3,7 @@
 
 // set DOTNET_TieredCompilation=0
 
+using System;
 using System.Runtime.CompilerServices;
 using System.Runtime.Intrinsics;
 using System.Numerics;