[libc++][type_traits] reference_{constructs|converts}_from_temporary with -Winvalid-specialization tests (#133946)

Addresses comment:
https://github.com/llvm/llvm-project/pull/128649/files#r2022341035

---------

Co-authored-by: Hristo Hristov <zingam@outlook.com>

Author: H-G-Hristov

libcxx/test/libcxx/type_traits/no_specializations.verify.cpp

@@ -156,6 +156,12 @@ SPECIALIZE_UTT(is_unbounded_array);     // expected-error 2 {{cannot be speciali
 #  if TEST_STD_VER >= 23
 SPECIALIZE_UTT(is_implicit_lifetime); // expected-error 2 {{cannot be specialized}}
 SPECIALIZE_UTT(is_scoped_enum);       // expected-error 2 {{cannot be specialized}}
+#    if __has_builtin(__reference_constructs_from_temporary)
+SPECIALIZE_BTT(reference_constructs_from_temporary); // expected-error 2 {{cannot be specialized}}
+#    endif
+#    if __has_builtin(__reference_converts_from_temporary)
+SPECIALIZE_BTT(reference_converts_from_temporary); // expected-error 2 {{cannot be specialized}}
+#    endif
 #  endif
 
 #  if TEST_STD_VER >= 26
@@ -177,8 +183,8 @@ struct std::conditional<true, S, S>; // expected-error {{cannot be specialized}}
 template <>
 struct std::enable_if<true, S>; // expected-error {{cannot be specialized}}
 
-#if TEST_STD_VER >= 20
+#  if TEST_STD_VER >= 20
 template <>
 struct std::integral_constant<S, {}>; // expected-error {{cannot be specialized}}
-#endif
+#  endif
 #endif