Need better error message when it fails to create a Mutex due to no-write permission to the '/tmp' folder on macOS or Linux

[daxian-dbw]

We consistently get issue reports in PSReadLine about an IOException when creating a Mutex object on macOS:

System.IO.IOException: The system cannot open the device or file specified. : 'PSReadLineHistoryFile_1525368525'
   at System.Threading.Mutex.CreateMutexCore(Boolean initiallyOwned, String name, Boolean& createdNew)
   at System.Threading.Mutex..ctor(Boolean initiallyOwned, String name)
   at Microsoft.PowerShell.PSConsoleReadLine.DelayedOneTimeInitialize()
   at Microsoft.PowerShell.PSConsoleReadLine.Initialize(Runspace runspace, EngineIntrinsics engineIntrinsics)
   at Microsoft.PowerShell.PSConsoleReadLine.ReadLine(Runspace runspace, EngineIntrinsics engineIntrinsics, CancellationToken cancellationToken)

I worked with a user on that issue and it turned out it was because the /tmp folder (mapped to /private/tmp) on the user's mac shows 755 for the permissions, namely no write permission for a non-root user. The user thought the permission change could be caused by Homebrew, and Mutex creation works fine after changing the permission to 777, see PowerShell/PSReadLine#1464 (comment)

The error message is not helpful to get to the root of the problem. Given it's a permission issue, it could be great if the error message could indicate the permission issue.