Another trial to fix ebvironment variables interpretation on Windows.

Author: asmorkalov

.github/workflows/OCV-PR-5.x-W10.yaml

@@ -131,7 +131,10 @@ jobs:
     - name: Accuracy:DNN_Classic
       timeout-minutes: 60
       if: ${{ always() && steps.build-opencv.outcome == 'success' }}
-      run: set OPENCV_FORCE_DNN_ENGINE="1" && cd ${{ github.workspace }}\build && bin\opencv_test_dnn.exe --skip_unstable --gtest_filter=${{ env.GTEST_FILTER_STRING }} --test_threads=%PARALLEL_JOBS%
+      run: |
+        set OPENCV_FORCE_DNN_ENGINE=1
+        cd ${{ github.workspace }}\build
+        bin\opencv_test_dnn.exe --skip_unstable --gtest_filter=${{ env.GTEST_FILTER_STRING }} --test_threads=%PARALLEL_JOBS%
     - name: Accuracy:features2d
       timeout-minutes: 60
       if: ${{ always() && steps.build-opencv.outcome == 'success' }}