[tests] Lower required kernel version of ECANCELED in TimeoutTest

My system running 5.15.43 also returns ECANCELED.

tests/io/TimeoutTest.cpp

@@ -9,6 +9,7 @@
 #include <cstdlib>
 #include <cstring>
 #include <memory>
+#include <ostream>
 
 #include "Common.hpp"
 #include "CountingPrivateSemaphore.hpp"
@@ -127,7 +128,8 @@ void writeTest() {
 	// write requests can't be canceled when in execution so this
 	// will return as interupted
 	const int err = errno;
-	ASSERT(err == EINTR || (EMPER_LINUX_GE("5.16.0") && err == ECANCELED));
+	ASSERT_MSG(err == EINTR || (EMPER_LINUX_GE("5.15.43") && err == ECANCELED),
+						 "Unexpected err: " << strerror(err) << "(" << err << ")");
 
 	emper::io::closeAndForget(efd);
 }