VS: Fix WINDOWS_EXPORT_ALL_SYMBOLS for object libraries

Teach Visual Studio generators to include object files from object
libraries in the list of objects whose symbols are to be exported.
The Makefile and Ninja generators already did this.  Update the
test to cover this case.

Reported-by: Bertrand Bellenot <Bertrand.Bellenot@cern.ch>
1 job for windows-export-all-fix-objlib
Status Job ID Name Coverage
  External
passed kwrobot-branch-check