Replace __cplusplus comparisons and dialect __has_feature checks with TEST_STD_VER.

This is a huge cleanup that helps make the libc++ test suite more portable.
Patch from STL@microsoft.com. Thanks STL!


git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@272716 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp

@@ -9,7 +9,9 @@
 
 // This is for bugs 18853 and 19118
 
-#if __cplusplus >= 201103L
+#include "test_macros.h"
+
+#if TEST_STD_VER >= 11
 
 #include <tuple>
 #include <functional>

test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp

@@ -21,7 +21,9 @@
 #include <string>
 #include <cassert>
 
-#if __cplusplus > 201103L
+#include "test_macros.h"
+
+#if TEST_STD_VER > 11
 
 struct Empty {};