Closing multiple instances simultaneously cause IOException with FolderExpansion.xml

[AlexEyler]

Repro:

1. Launch multiple instances (at least 3) of VS 2017 (with VS-Macros installed).
2. Open solutions in each VS.
3. Right click on the VS icon on the taskbar and select "Close all windows".
   Expected:
   All windows close
   Actual:
   At least one instances gets the following error:

---------------------------
Microsoft Visual Studio
---------------------------
The process cannot access the file 'C:\Users\{username}\AppData\Local\Microsoft\VisualStudio\15.0_80f42237\FolderExpansion.xml' because it is being used by another process.
---------------------------
OK   
---------------------------

It looks like this file is created/used by the VS-Macros extension.

[justcla]

Thanks Alex.
Pratik Nadagouda (@prnadago) , This looks like one of many issues that arise when using Macros with multiple instances of Visual Studio open. Looking at the path (above) we can see that Macros is using shared locations - instead of per-instance locations.
Not sure how challenging it will be to make Macros work properly with multiple instance open.

[AlexEyler]

Note: when I say "instance", I still mean the same installation of VS. You likely need to consider adding a mutex around access to the file.

[justcla]

Alex Eyler (@AlexEyler), any chance you could submit a PR with a fix? ;-)

[AlexEyler]

If I get some free time, sure - can't promise anything though, I don't know the code at all.

[justcla]

Oleg Tkachenko (@olegtk), FYI.