[libcxx] [test] Replace _LIBCPP_STD_VER with TEST_STD_VER.

This replaces every occurrence of _LIBCPP_STD_VER in the tests with
TEST_STD_VER. Additionally, for every affected
file, #include "test_macros.h" is being added explicitly if it wasn't
already there.

https://reviews.llvm.org/D26294

llvm-svn: 286007
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
index 490dc16..d9471b5 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
@@ -15,6 +15,8 @@
 #include <type_traits>
 #include <cassert>
 
+#include "test_macros.h"
+
 int main()
 {
     typedef std::divides<int> F;
@@ -23,7 +25,7 @@
     static_assert((std::is_same<int, F::second_argument_type>::value), "" );
     static_assert((std::is_same<int, F::result_type>::value), "" );
     assert(f(36, 4) == 9);
-#if _LIBCPP_STD_VER > 11
+#if TEST_STD_VER > 11
     typedef std::divides<> F2;
     const F2 f2 = F2();
     assert(f2(36, 4) == 9);