AK: Allow Optional<T> to be used in constant expressions

Author: https://github.com/yyny
Commit: a059ab4677
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4310
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/DanShaders
Reviewed-by: https://github.com/Hendiadyoin1
Reviewed-by: https://github.com/alimpfard ✅

Libraries/LibTest/Macros.h

@@ -130,6 +130,9 @@ bool assume(T const& expression, StringView expression_string, SourceLocation lo
     return true;
 }
 
+template<typename T>
+consteval void expect_consteval(T) { }
+
 }
 
 #define EXPECT(...)                                    \
@@ -179,6 +182,8 @@ bool assume(T const& expression, StringView expression_string, SourceLocation lo
         ::Test::set_current_test_result(::Test::TestResult::Failed);                       \
     } while (false)
 
+#define EXPECT_CONSTEVAL(...) ::Test::expect_consteval(__VA_ARGS__)
+
 // To use, specify the lambda to execute in a sub process and verify it exits:
 //  EXPECT_CRASH("This should fail", []{
 //      return Test::Crash::Failure::DidNotCrash;