Why is JIT not enabled on devices like Espruino WiFi even if they are on the latest firmware?

the esprima offline minifier makes it into

function (a,b,c) {"jit";c===undefined&&(c=1),b===undefined&&(b=0);for(let d=this.idx+b;d<this.next-a.length;d+=c){if(this.buffer[d]!==a[0])continue;let b=d;for(let e=1;e<a.length;e++)this.buffer[d+e]!==a[e]&&(b=-1,e=a.length-1);if(b!==-1)return b}return-1}

so there is comma operator and ifs changed into condition && body and continue is still there

when uploading from IDE I see

JIT SyntaxError: Got continue expected EOF
 at line 1 col 143 in find.js
...){if(this.buffer[d]!==a[0])continue;let b=d;for(let e=1;e<a....
                              ^