Fix test CI targets to reuse the env variables computed in the Makefile

Author: mattam82

.github/workflows/ci.yml

@@ -56,7 +56,7 @@ jobs:
         run: opam exec -- dune build @install
 
       - name: Run tests
-        run: opam exec -- dune test
+        run: opam exec -- make test
 
 #      - name: Format code
 #        run: opam exec -- dune build --auto-promote @fmt

.github/workflows/debug-ci.yml

@@ -49,7 +49,7 @@ jobs:
         run: opam exec -- dune build @install
 
       - name: Run tests
-        run: opam exec -- dune test
+        run: opam exec -- make test
 
       - name: Format code
         run: opam exec -- dune build --auto-promote @fmt