unix: improve flaky solaris test logging

relates to golang/go#58259

Change-Id: I47bbf4afb59b6e98571297ba53d7f9370712e030
Reviewed-on: https://go-review.googlesource.com/c/sys/+/465015
Reviewed-by: Bryan Mills <bcmills@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

unix/syscall_solaris_test.go

@@ -183,7 +183,9 @@ func TestEventPortErrors(t *testing.T) {
 	timeout.Nsec = 1
 	_, err = port.GetOne(timeout)
 	if err != unix.ETIME {
-		t.Errorf("unexpected lack of timeout")
+		// See https://go.dev/issue/58259
+		// Perhaps we sometimes get EINTR ???
+		t.Errorf("port.GetOne(%v) returned error %v, want %v", timeout, err, unix.ETIME)
 	}
 	err = port.DissociateFd(uintptr(0))
 	if err == nil {