VSIX Incremental Build is Broken

[benvillalobos]

Issue Description

Running build.cmd -pack should always generate new vsix packages when there's something new to build. Today it looks as if incremental build specifically for these packages is broken in some way, or doesn't exist.

Steps to Reproduce

build.cmd -pack
make a change
build.cmd -pack

Expected Behavior

All generated VSIX's get overwritten when relevant

Actual Behavior

No new VSIX is generated, or it's generated with stale bits (can't confirm, but I suspect)

[rainersigwald]

When I looked at this last it wasn't a problem with our repo but with some of the tasks/targets we use. So this may track nailing those down and reporting them, then adopting the updates.