Shorten test time for KeyFrameIntervalTestLarge

This commit reduces the number of frames used in the test from 150 to
75.

Change-Id: Ief259583b071f1598eeb4cf3a82c8b04ef24e5c7
diff --git a/test/kf_test.cc b/test/kf_test.cc
index 9f8f52a..0067796 100644
--- a/test/kf_test.cc
+++ b/test/kf_test.cc
@@ -104,7 +104,7 @@
 TEST_P(KeyFrameIntervalTestLarge, KeyFrameIntervalTest) {
   libaom_test::I420VideoSource video("hantro_collage_w352h288.yuv", 352, 288,
                                      cfg_.g_timebase.den, cfg_.g_timebase.num,
-                                     0, 150);
+                                     0, 75);
   ASSERT_NO_FATAL_FAILURE(RunLoop(&video));
   ASSERT_EQ(is_kf_interval_violated_, false) << kf_dist_param_;
 }