rpcrt4: NdrClientContextMarshall/Unmarshall should both increment the buffer pointer.

dlls/rpcrt4/ndr_marshall.c

@@ -4347,8 +4347,10 @@ void WINAPI NdrClientContextMarshall(PMIDL_STUB_MESSAGE pStubMsg,
 {
     TRACE("(%p, %p, %d): stub\n", pStubMsg, ContextHandle, fCheck);
     /* FIXME: what does fCheck do? */
-    return NDRCContextMarshall(ContextHandle,
+    NDRCContextMarshall(ContextHandle,
                         pStubMsg->Buffer);
+
+    pStubMsg->Buffer += cbNDRContext;
 }
 
 /***********************************************************************
@@ -4359,10 +4361,12 @@ void WINAPI NdrClientContextUnmarshall(PMIDL_STUB_MESSAGE pStubMsg,
                                        RPC_BINDING_HANDLE BindHandle)
 {
     TRACE("(%p, %p, %p): stub\n", pStubMsg, pContextHandle, BindHandle);
-    return NDRCContextUnmarshall(pContextHandle,
+    NDRCContextUnmarshall(pContextHandle,
                           BindHandle,
                           pStubMsg->Buffer,
                           pStubMsg->RpcMsg->DataRepresentation);
+
+    pStubMsg->Buffer += cbNDRContext;
 }
 
 void WINAPI NdrServerContextMarshall(PMIDL_STUB_MESSAGE pStubMsg,