message: fix array deprecation warnings
diff: @@ -200,7 +200,7 @@ TYPED_TEST(Array, CanBeMoveConstructedToADifferentExecutor)
  TYPED_TEST(Array, MoveConstructedFromArrayExecutorlessIsEmpty)
  {
  - gko::Array<TypeParam> a{std::move(this->x)};
  + gko::array<TypeParam> a{std::move(this->x)};
  a = std::move(this->x);
  @@ -211,7 +211,7 @@ TYPED_TEST(Array, MoveConstructedFromArrayExecutorlessIsEmpty)
  TYPED_TEST(Array, MoveConstructedFromArraySameExecutorIsEmpty)
  {
  - gko::Array<TypeParam> a{this->exec, std::move(this->x)};
  + gko::array<TypeParam> a{this->exec, std::move(this->x)};
  ASSERT_EQ(this->x.get_executor(), this->exec);
  ASSERT_EQ(this->x.get_num_elems(), 0);
  @@ -220,7 +220,7 @@ TYPED_TEST(Array, MoveConstructedFromArraySameExecutorIsEmpty)
  TYPED_TEST(Array, MoveConstructedFromArrayDifferentExecutorIsEmpty)
  {
  - gko::Array<TypeParam> a{gko::ReferenceExecutor::create(),
  + gko::array<TypeParam> a{gko::ReferenceExecutor::create(),
  std::move(this->x)};
  ASSERT_EQ(this->x.get_executor(), this->exec);
  @@ -297,7 +297,7 @@ TYPED_TEST(Array, CanBeMovedFromExecutorlessArray)
  TYPED_TEST(Array, MovedFromArrayExecutorlessIsEmpty)
  {
  - gko::Array<TypeParam> a;
  + gko::array<TypeParam> a;
  a = std::move(this->x);
  @@ -308,7 +308,7 @@ TYPED_TEST(Array, MovedFromArrayExecutorlessIsEmpty)
  TYPED_TEST(Array, MovedFromArraySameExecutorIsEmpty)
  {
  - gko::Array<TypeParam> a{this->exec};
  + gko::array<TypeParam> a{this->exec};
  a = std::move(this->x);
  @@ -319,7 +319,7 @@ TYPED_TEST(Array, MovedFromArraySameExecutorIsEmpty)
  TYPED_TEST(Array, MovedFromArrayDifferentExecutorIsEmpty)
  {
  - gko::Array<TypeParam> a{gko::ReferenceExecutor::create()};
  + gko::array<TypeParam> a{gko::ReferenceExecutor::create()};
  a = std::move(this->x);
  