🧪💅 Melt (non-)free-threading Win jobs a matrix

Previously, these were defined through two separate matrices but there
is no technical reason to keep them like that.

Author: webknjaz

.github/workflows/build.yml

@@ -179,7 +179,9 @@ jobs:
         run: make check-c-globals
 
   build_windows:
-    name: 'Windows'
+    name: >-
+      Windows
+      ${{ fromJSON(matrix.free-threading && '(free-threading)' || '' }}
     needs: check_source
     if: fromJSON(needs.check_source.outputs.run_tests)
     strategy:
@@ -188,24 +190,13 @@ jobs:
         - Win32
         - x64
         - arm64
+        free-threading:
+        - false
+        - true
     uses: ./.github/workflows/reusable-windows.yml
     with:
       arch: ${{ matrix.arch }}
-
-  build_windows_free_threading:
-    name: 'Windows (free-threading)'
-    needs: check_source
-    if: fromJSON(needs.check_source.outputs.run_tests)
-    strategy:
-      matrix:
-        arch:
-        - Win32
-        - x64
-        - arm64
-    uses: ./.github/workflows/reusable-windows.yml
-    with:
-      arch: ${{ matrix.arch }}
-      free-threading: true
+      free-threading: ${{ matrix.free-threading }}
 
   build_macos:
     name: 'macOS'
@@ -571,7 +562,6 @@ jobs:
     - build_ubuntu_ssltests
     - build_wasi
     - build_windows
-    - build_windows_free_threading
     - test_hypothesis
     - build_asan
     - build_tsan
@@ -607,7 +597,6 @@ jobs:
             build_ubuntu_ssltests,
             build_wasi,
             build_windows,
-            build_windows_free_threading,
             build_asan,
             build_tsan,
             build_tsan_free_threading,