Update Windows build chain to MSVC 2022

[ericmehl]

This will keep us up to date with the VFX reference platform, and it should fix a bug MSVC introduces causing some disk partition types to not be usable : https://groups.google.com/g/gaffer-dev/c/zuAhqDFIl50

It will also hopefully allow useful ASan builds on Windows. Currently something in TBB causes ASan to error at startup, but recent MSVC 2022 builds have added the ability to continue on errors and collect a list of them after running.

[johnhaddon]

Do you think it'd be reasonable to get this in for 1.4, @ericmehl?

[ericmehl]

Yeah, I think it should be possible. Hard to know with MSVC, but the transition to 2019 wasn't too bad.

[boberfly]

I was successful in building Gaffer with VS2022 MSVC 14.3, it wasn't many patches but I can upstream them - it was mostly making MSVC_VERSION configurable for SCons and a few warning suppressors.

[johnhaddon]

Maybe we can aim to get this done for 1.5 @ericmehl?

[ericmehl]

Yeah, we're overdue for updating to 2022 so prioritizing it for 1.5 would be great. @boberfly, if you want to put up a PR to GafferHQ / Dependencies, that would be a great help. I think it should target a new branch called 8_maintenance_msvc2022, based on the current names of the branches?

[johnhaddon]

Closing as done in #6044.