More care with quoting to make PowerShell happy

[jennybc]

Addresses #2099

I was able to reproduce this and this PR rescues things for me.

The big idea is to provide the task's kibbles and bits individually and let VS Code figure out how to quote it, with stern instructions to use ShellQuoting.Strong:

Strong string quoting should be used. This for example uses " for Windows cmd and ' for bash and PowerShell. Strong quoting treats arguments as literal strings. Under PowerShell echo 'The value is $(2 * 3)' will print The value is $(2 * 3)

https://code.visualstudio.com/api/references/vscode-api#ShellQuoting

[jennybc]

I'm tagging you @DavisVaughan because I think you're probably in the best position to experience this before and after, like me. But happy to get a review from anyone.