Update llpc to handle new version of llvm

Handle upstream llvm changes for llvm/llvm-project@7b9d73c
[NFC] Remove Type::getInt8PtrTy (#71029)

shared/continuations/lib/LowerAwait.cpp

@@ -171,7 +171,7 @@ static void processContinuations(
   //    co.flag = llvm.coro.suspend.retcon
   //       unreachable
   auto &Context = M.getContext();
-  auto *I8Ptr = Type::getInt8PtrTy(Context);
+  auto *I8Ptr = PointerType::getUnqual(Context);
   auto *I32 = Type::getInt32Ty(Context);
   auto *I64 = Type::getInt64Ty(Context);