VCL SysEnvData: add Invalid Platform and Toolkit

I accidently almost introduced some subtle sytactic error in Qt,
because the default platform and toolkit values are actually valid.

So add an Invalid value to both enum classes and then sprinkle
some asserts, so these tests aren't working on invalid data.

Thanks Michael Weghorn for catching this in review.

Change-Id: Ic6a0764dfc5168181251023f4d1c66ffa32651d8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/134882
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

0 files changed, 0 insertions, 0 deletions