include/swift/Basic: fix deprecation warnings

These are deprecation warnings
```
include/swift/Basic/type_traits.h:49:29: warning: builtin __has_trivial_constructor is deprecated; use __is_trivially_constructible instead [-Wdeprecated-builtins]
  static const bool value = __has_trivial_constructor(T);
                            ^
include/swift/Basic/type_traits.h:61:29: warning: builtin __has_trivial_destructor is deprecated; use __is_trivially_destructible instead [-Wdeprecated-builtins]
  static const bool value = __has_trivial_destructor(T);
                            ^
2 warnings generated.
```

Author: MaxDesiatov

include/swift/Basic/type_traits.h

@@ -46,7 +46,7 @@ struct IsTriviallyConstructible {
   // libc++ and MSVC implement is_trivially_constructible.
   static const bool value = std::is_trivially_constructible<T>::value;
 #elif __has_feature(has_trivial_constructor) || __GNUC__ >= 5
-  static const bool value = __has_trivial_constructor(T);
+  static const bool value = __is_trivially_constructible(T);
 #else
 #  error "Not implemented"
 #endif