Created Issue: Access is denied error when profiling standalone script [811]

In VS, without any project open, analyze/launch node.js profiling
Select a script, I picked "Nodejs\Prerequisites\generate.js"
Doesn't matter for the working dir
Accept the default to save the .njsperf file next to the script

You'll get this message box:
```
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System.ComponentModel.Win32Exception (0x80004005): Access is denied

at Microsoft.NodejsTools.LogGeneration.TraceLog.Start(String filename, String sessionName)

at Microsoft.NodejsTools.LogParsing.LogConverter.Process()

at Microsoft.NodejsTools.LogParsing.LogConverter.Main(String[] args)
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OK
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```