VS: Fix SBCS support for object libraries

In commit 3a53005f (Build object library targets in VS, 2012-03-12,
v2.8.8~29^2~13) we updated the condition for unicode but accidentally
left out the SBCS case support for object libraries.

Fixes: #19469
2 jobs for object-library-sbcs
Status Job ID Name Coverage
  External
passed ghostflow-check-master

passed ghostflow-stager