It doesn't look like that tested LuaJIT. The JIT part or the faster interpreter.
Assuming apples-to-apples JIT technology, Pawn would still be faster because it's a barebones coding environment. Its semantics are roughly similar to C, but with even fewer features. The only definite way to outdo that is with something like Terra[0] where the program has meta-level control over its own compilation and execution.
Be careful of getting drawn in to "newer is better".
You're right - newer is not necessarily better. But active development and recent releases are usually a good proxy for at least a chance of further improvements.
Newer might not be but maintained and popular definitely is.
You may also have a look at SourcePawn from AlliedModders who enhanced it a lot.