Fix Hwloc handling for Windows CI

The previous fix didn't properly handle the Windows case where
ifelse(Sys.iswindows(), 0, ...) would return 0, causing the min()
to always select 0, leading to an empty string parse error.

Now we ensure at least 1 core even on Windows by wrapping the entire
ifelse expression with max(..., 1).

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: ChrisRackauckas

test/runtests.jl

@@ -23,7 +23,7 @@ const RETESTITEMS_NWORKERS = if GROUP == "wrappers"
 else
     parse(
         Int, get(ENV, "RETESTITEMS_NWORKERS",
-            string(min(ifelse(Sys.iswindows(), 0, max(Hwloc.num_physical_cores(), 1)), 4))
+            string(min(max(ifelse(Sys.iswindows(), 0, Hwloc.num_physical_cores()), 1), 4))
         )
     )
 end