gh-128446: Skip Windows CI for Unix build system changes (#128450)

Co-authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>
Authored-by: Adam Turner <9087854+aa-turner@users.noreply.github.com>

.github/workflows/build.yml

@@ -154,7 +154,7 @@ jobs:
       Windows
       ${{ fromJSON(matrix.free-threading) && '(free-threading)' || '' }}
     needs: build-context
-    if: fromJSON(needs.build-context.outputs.run-tests)
+    if: fromJSON(needs.build-context.outputs.run-windows-tests)
     strategy:
       fail-fast: false
       matrix:
@@ -654,13 +654,19 @@ jobs:
             build_ubuntu,
             build_ubuntu_ssltests,
             build_wasi,
-            build_windows,
             build_asan,
             build_tsan,
             test_hypothesis,
             '
             || ''
           }}
+          ${{
+            !fromJSON(needs.build-context.outputs.run-windows-tests)
+            && '
+            build_windows,
+            '
+            || ''
+          }}
           ${{
             !fromJSON(needs.build-context.outputs.run-ci-fuzz)
             && '

.github/workflows/reusable-context.yml

@@ -26,6 +26,9 @@ on:  # yamllint disable-line rule:truthy
       run-tests:
         description: Whether to run the regular tests
         value: ${{ jobs.compute-changes.outputs.run-tests  }}  # bool
+      run-windows-tests:
+        description: Whether to run the Windows tests
+        value: ${{ jobs.compute-changes.outputs.run-windows-tests }}  # bool
       run-windows-msi:
         description: Whether to run the MSI installer smoke tests
         value: ${{ jobs.compute-changes.outputs.run-windows-msi }}  # bool
@@ -44,6 +47,7 @@ jobs:
       run-docs: ${{ steps.changes.outputs.run-docs }}
       run-tests: ${{ steps.changes.outputs.run-tests }}
       run-windows-msi: ${{ steps.changes.outputs.run-windows-msi }}
+      run-windows-tests: ${{ steps.changes.outputs.run-windows-tests }}
     steps:
     - name: Set up Python
       uses: actions/setup-python@v5