Tests: fixed grpc.t TODO hang on win32.

The eval + alarm model was replaced with non-blocking I/O
for the same reasons as in d0025a0dead7.

grpc.t

diff --git a/grpc.t b/grpc.t
index cb2004d..f61cb36 100644
--- a/grpc.t
+++ b/grpc.t
@@ -719,17 +719,11 @@
 			{ name => 'te', value => 'trailers', mode => 2 }]});
 
 		if (!$extra{reuse}) {
-			eval {
-				local $SIG{ALRM} = sub { die "timeout\n" };
-				alarm(5);
+			if (IO::Select->new($server)->can_read(5)) {
+				$client = $server->accept();
 
-				$client = $server->accept() or return;
-
-				alarm(0);
-			};
-			alarm(0);
-			if ($@) {
-				log_in("died: $@");
+			} else {
+				log_in("timeout");
 				# connection could be unexpectedly reused
 				goto reused if $client;
 				return undef;