gf_pyr_height_test: use Values() w/explicit values

this is simpler than using ValuesIn() with an initializer list and
should fix some compilation issues with older toolchains, e.g., gcc
4.8.x

BUG=aomedia:2596

Change-Id: I437124dbde31b3d9d04432e3876248a074b44cfb
diff --git a/test/gf_pyr_height_test.cc b/test/gf_pyr_height_test.cc
index 518b01e..0befcdf 100644
--- a/test/gf_pyr_height_test.cc
+++ b/test/gf_pyr_height_test.cc
@@ -151,6 +151,6 @@
 }
 
 AV1_INSTANTIATE_TEST_CASE(GFPyrHeightTest, NONREALTIME_TEST_MODES,
-                          ::testing::ValuesIn({ AOM_Q, AOM_VBR }),
+                          ::testing::Values(AOM_Q, AOM_VBR),
                           ::testing::ValuesIn(kTestParams));
 }  // namespace