Refactor flaky file list to environment variable

Author: user202729

.github/workflows/ci-meson.yml

@@ -21,6 +21,8 @@ jobs:
   test:
     name: Conda (${{ matrix.os }}, Python ${{ matrix.python }}, ${{ matrix.tests }}${{ matrix.editable && ', editable' || '' }})
     runs-on: ${{ matrix.os }}-latest
+    env:
+      SEPARATELY_TESTED_FLAKY_FILES: "src/sage/libs/singular/function.pyx src/sage/rings/polynomial/plural.pyx"
 
     strategy:
       fail-fast: false
@@ -170,7 +172,7 @@ jobs:
             pytest -rfEs -s src
             ./sage -t ${{
               matrix.tests == 'all' &&
-              '--all-except="src/sage/libs/singular/function.pyx src/sage/rings/polynomial/plural.pyx"' ||
+              '--all-except="$SEPARATELY_TESTED_FLAKY_FILES"' ||
               '--new --long' }} -p4 --format github
           fi
 
@@ -181,7 +183,7 @@ jobs:
         shell: bash -l {0}
         run: |
           for i in {1..5}; do
-            ./sage -t -p4 --format github src/sage/libs/singular/function.pyx src/sage/rings/polynomial/plural.pyx && break
+            ./sage -t -p4 --format github $SEPARATELY_TESTED_FLAKY_FILES && break
           done
 
       - name: Check that all modules can be imported