Tests js cpu profile in timeline.

Main Thread
EvaluateScript Properties:
{
    data : {
    }
    endTime : <number>
    startTime : <number>
    type : "EvaluateScript"
}
FAIL: missing functions:
worker2.onmessage
DedicatedWorker Thread
DedicatedWorker Thread
EvaluateScript Properties:
{
    data : {
        columnNumber : <number>
        frame : <string>
        lineNumber : <number>
        url : .../inspector/tracing/resources/worker.js
    }
    endTime : <number>
    frameId : <string>
    startTime : <number>
    type : "EvaluateScript"
}
FAIL: missing functions:
onmessage