[clang] Fix include for 7ead2d8

clang/lib/CodeGen/MCDCState.h:33:11: error: no template named 'SmallVector' in namespace 'llvm'
   33 |     llvm::SmallVector<std::array<int, 2>> Indices;
      |     ~~~~~~^

clang/lib/CodeGen/MCDCState.h

@@ -14,6 +14,7 @@
 #define LLVM_CLANG_LIB_CODEGEN_MCDCSTATE_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/ProfileData/Coverage/MCDCTypes.h"
 
 namespace clang {