foreign thread signal forwarding: swap tests to support OpenBSD

On OpenBSD, With the tests in the original order, with the parent
process setting a signal handler and accepting a foreign signal, the
child process test would block busy waiting when the child process
called exit.

From looking at kdump the child process is busy waiting on sched_yield
outside the perl process.

Since this appears to be OpenBSD specific (other BSD, linux, MacOS
work fine), and the sequence causing the problem seems unlikely
outside a test scenario I'm not going to investigate further.

Author: tonycoz

ext/XS-APItest/t/thread.t

@@ -38,14 +38,6 @@ SKIP:
     }
 }
 
-{
-    my $saw_signal;
-    local $SIG{USR1} = sub { ++$saw_signal };
-    my $pid = make_signal_thread();
-    join_signal_thread($pid);
-    ok($saw_signal, "saw signal sent to non-perl thread");
-}
-
 {
     $Config{d_fork}
       or skip "Need fork", 1;
@@ -68,4 +60,13 @@ SKIP:
     }
 }
 
+{
+    my $saw_signal;
+    local $SIG{USR1} = sub { ++$saw_signal };
+    my $pid = make_signal_thread();
+    join_signal_thread($pid);
+    ok($saw_signal, "saw signal sent to non-perl thread");
+}
+
+
 done_testing();