[NFC] Drop dead code from common.h

tests/common/common.h

@@ -343,80 +343,6 @@ bool check_equal_values(const sycl::marray<T, numElements>& lhs,
 }
 #endif
 
-/** Enables concept checking ahead of the Concepts TS
- *  Idea for macro taken from Eric Niebler's range-v3
- */
-#define REQUIRES_IMPL(B) typename std::enable_if<(B), int>::type = 1
-#define REQUIRES(...) REQUIRES_IMPL((__VA_ARGS__))
-
-/**
- * @brief Transforms the input type into a dependant type and performs
- *        an enable_if based on the condition.
- *
- *        Useful for disabling a member function based on a template parameter
- *        of the class.
- * @param typeName Non-dependant type to be made dependant
- * @param condition The condition specifying when the template
- *        should be enabled. typeName can occur within this expression.
- */
-#define ENABLE_IF_DEPENDANT(typeName, condition)                               \
-  typename overloadDependantT = typeName,                                      \
-           typename = typename std::enable_if <                                \
-                          std::is_same<typeName, overloadDependantT>::value && \
-                      (condition) > ::type
-
-template <bool condition, typename F1, typename F2,
-          bool same_return_type =
-              std::is_same<typename std::result_of<F1&()>::type,
-                           typename std::result_of<F2&()>::type>::value>
-struct if_constexpr_impl;
-
-template <bool condition, typename F1, typename F2>
-struct if_constexpr_impl<condition, F1, F2, true> {
-  static constexpr auto result(const F1& f1, const F2& f2) -> decltype(f1()) {
-    return condition ? f1() : f2();
-  }
-};
-
-template <typename F1, typename F2>
-struct if_constexpr_impl<true, F1, F2, false> {
-  static constexpr auto result(const F1& f1, const F2&) -> decltype(f1()) {
-    return f1();
-  }
-};
-
-template <typename F1, typename F2>
-struct if_constexpr_impl<false, F1, F2, false> {
-  static constexpr auto result(const F1&, const F2& f2) -> decltype(f2()) {
-    return f2();
-  }
-};
-
-/**
- * @brief Library implementation for C++17's compile-time if-statement so that
- * it works in C++11. Generates a call to the invocable object `f1` if
- * `condition == true` at compile-time, otherwise a call to `f2` is generated.
- */
-template <bool condition, typename F1, typename F2,
-          typename R = typename std::conditional<
-              condition, typename std::result_of<F1&()>::type,
-              typename std::result_of<F2&()>::type>::type>
-inline R if_constexpr(const F1& f1, const F2& f2) {
-  return if_constexpr_impl<condition, F1, F2>::result(f1, f2);
-}
-
-/**
- * @brief Library implementation for C++17's compile-time if-statement so that
- * it works in C++11. Generates a call to the invocable object `f` if
- * `condition == true` at compile-time, otherwise no code is generated.
- */
-template <bool condition, typename F>
-inline void if_constexpr(const F& f) {
-  if (condition) {
-    f();
-  }
-}
-
 /**
  * @brief Tag to denote mapping of integer coordinates to real scale
  *