Remove double include of <tuple> and <tr1/tuple> in third_party/googletest BUILD.gn

Related: https://chromium-review.googlesource.com/c/chromium/src/+/1004440
Change-Id: I6040414e5d980c7d98a7a38e136cd8d2349a5c4c
Reviewed-on: https://chromium-review.googlesource.com/1017805
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52862}

third_party/googletest/BUILD.gn

@@ -15,8 +15,11 @@ config("gtest_config") {
     # and other systems, we tell gtest to always use its internal engine.
     "GTEST_HAS_POSIX_RE=0",
 
+    # Enables C++11 features.
     "GTEST_LANG_CXX11=1",
-    "GTEST_HAS_STD_TUPLE=1",
+
+    # Prevents gtest from including both <tr1/tuple> and <tuple>.
+    "GTEST_HAS_TR1_TUPLE=0",
   ]
 
   # Gtest headers need to be able to find themselves.