test/wasm/limits.js - Slow test timeout >300s

https://ci.dot.net/job/Microsoft_ChakraCore/job/master/job/daily_slow_x64_test/156/consoleFull#18131162893c95c4dd-a7e3-4a01-8f84-41941e4287c5Z

```
interpreted\rl.results.log:wasm (limits.js ( -wasm -args --no-verbose --end 4 -endargs) exe) -- failed : exec time=300
```