Fix invalid self move assignment.

asio/src/tests/unit/posix/stream_descriptor.cpp

diff --git a/asio/src/tests/unit/posix/stream_descriptor.cpp b/asio/src/tests/unit/posix/stream_descriptor.cpp
index 33dbcbc..72e1f95 100644
--- a/asio/src/tests/unit/posix/stream_descriptor.cpp
+++ b/asio/src/tests/unit/posix/stream_descriptor.cpp
@@ -60,7 +60,7 @@
     posix::stream_descriptor descriptor2(ios, native_descriptor1);
 
 #if defined(ASIO_HAS_MOVE)
-    posix::stream_descriptor descriptor3(std::move(descriptor3));
+    posix::stream_descriptor descriptor3(std::move(descriptor2));
 #endif // defined(ASIO_HAS_MOVE)
 
     // basic_stream_descriptor operators.