Replace testing::tuple with std::tuple (x2)

The test code is built as c++11 and the testing:: implementation has
been removed from newer versions of googletest.

This updates a few instances after:
a543df590 Replace testing::tuple with std::tuple

BUG=aomedia:2582

Change-Id: Ic828b32cf1edbff05b48b8e9e5a2199fcf178c26
(cherry picked from commit 9b224eab7c37f2488ea96bdf60f58cd5615f9e7a)
diff --git a/test/warp_filter_test_util.cc b/test/warp_filter_test_util.cc
index 325fc23..faea9f5 100644
--- a/test/warp_filter_test_util.cc
+++ b/test/warp_filter_test_util.cc
@@ -495,7 +495,7 @@
   const int is_beta_zero = GET_PARAM(2);
   const int is_gamma_zero = GET_PARAM(3);
   const int is_delta_zero = GET_PARAM(4);
-  const int out_w = std::get<0>(param), out_h = ::testing::get<1>(param);
+  const int out_w = std::get<0>(param), out_h = std::get<1>(param);
   const int bd = std::get<3>(param);
   const int mask = (1 << bd) - 1;
   int sub_x, sub_y;
@@ -558,7 +558,7 @@
   const int is_beta_zero = GET_PARAM(2);
   const int is_gamma_zero = GET_PARAM(3);
   const int is_delta_zero = GET_PARAM(4);
-  const int out_w = std::get<0>(param), out_h = ::testing::get<1>(param);
+  const int out_w = std::get<0>(param), out_h = std::get<1>(param);
   const int bd = std::get<3>(param);
   const int num_iters = std::get<2>(param);
   const int mask = (1 << bd) - 1;