use new llvm::Optional API

`getValue` -> `value`
`getValueOr` -> `value_or`
`hasValue` -> `has_value`
`map` -> `transform`

The old API will be deprecated in the rebranch.
To avoid merge conflicts, use the new API already in the main branch.

rdar://102362022

lib/Serialization/ModuleFileSharedCore.cpp

@@ -1402,7 +1402,7 @@ ModuleFileSharedCore::ModuleFileSharedCore(
           }
 
           Dependencies.push_back(
-              {blobData, spiBlob, importKind.getValue(), scoped});
+              {blobData, spiBlob, importKind.value(), scoped});
           break;
         }
         case input_block::LINK_LIBRARY: {