Global tool .cmd shims will show "Terminate Batch Job" prompt on CTRL+C

[dsplaisted]

On Windows, for tools where the runner type is executable, we create a .cmd script shim that invokes the tool. The shim goes in the dotnet tools folder which is on the path.

Unfortunately, batch files like this will generate an extra Terminate batch job (Y/N) prompt when CTRL+C is pressed. We ran into this for dnx in #49623.

We should probably generate both a PowerShell and a .cmd shell shim script, so that for users of PowerShell, that script will be preferred and they won't get the extra termination prompt when CTRL+C is pressed.

The logic to create the script is in the ShellShimRepository class.