Tests: removed TODO for HTTP/2 duplicate settings.

It's not broken in 1.12 but actually a regression of 645ed7112a01 (1.13.2).

h2.t

diff --git a/h2.t b/h2.t
index 603b1a1..34c79cd 100644
--- a/h2.t
+++ b/h2.t
@@ -772,9 +772,6 @@
 $sum = eval join '+', map { $_->{length} } @data;
 is($sum, 2**16 - 1, 'iws duplicate - default stream window');
 
-TODO: {
-local $TODO = 'not yet' unless $t->has_version('1.13.9');
-
 # this should effect in extra stream window octect
 # $s->h2_settings(0, 0x4 => 42, 0x4 => 2**16);
 {
@@ -796,8 +793,6 @@
 $sum = eval join '+', map { $_->{length} } @data;
 is($sum, 80, 'iws duplicate - updated stream window 2');
 
-}
-
 # probe for negative available space in a flow control window
 
 # 6.9.2.  Initial Flow-Control Window Size