[gtest] Use `std::index_sequence` and friends instead of rolling our own

* Applies for `std::index_sequence`, `std::make_index_sequence`, and `std::index_sequence_for` replacing `IndexSequence`, `MakeIndexSequence` and IndexSequenceFor`
* Also deleted implementation helper `DoubleSequence`
* The standard interfaces [have been in the standard library since C++14](https://en.cppreference.com/w/cpp/utility/integer_sequence), which [is the minimum supported C++ version by Google Test](https://github.com/google/oss-policies-info/blob/main/foundational-cxx-support-matrix.md)

PiperOrigin-RevId: 621939977
Change-Id: Id264266f08da66c0fa2a6e6fbb8f86fd3cb3a421

1 files changed, 0 insertions, 16 deletions

diff --git a/googletest/test/gtest_unittest.cc b/googletest/test/gtest_unittest.cc
index 5d7cfb0..edbe2ea 100644
--- a/googletest/test/gtest_unittest.cc
+++ b/googletest/test/gtest_unittest.cc
@@ -7482,22 +7482,6 @@ TEST(NativeArrayTest, WorksForTwoDimensionalArray) {
   EXPECT_EQ(a, na.begin());
 }
 
-// IndexSequence
-TEST(IndexSequence, MakeIndexSequence) {
-  using testing::internal::IndexSequence;
-  using testing::internal::MakeIndexSequence;
-  EXPECT_TRUE(
-      (std::is_same<IndexSequence<>, MakeIndexSequence<0>::type>::value));
-  EXPECT_TRUE(
-      (std::is_same<IndexSequence<0>, MakeIndexSequence<1>::type>::value));
-  EXPECT_TRUE(
-      (std::is_same<IndexSequence<0, 1>, MakeIndexSequence<2>::type>::value));
-  EXPECT_TRUE((
-      std::is_same<IndexSequence<0, 1, 2>, MakeIndexSequence<3>::type>::value));
-  EXPECT_TRUE(
-      (std::is_base_of<IndexSequence<0, 1, 2>, MakeIndexSequence<3>>::value));
-}
-
 // ElemFromList
 TEST(ElemFromList, Basic) {
   using testing::internal::ElemFromList;