ci: write e2e test logs to file

Write e2e test logs to file in addition to standard output in order to make debugging easier. CCI will truncate output over 50M.

Closes https://github.com/ethereum-optimism/client-pod/issues/319

.circleci/config.yml

@@ -856,11 +856,16 @@ jobs:
       - run:
           name: run tests
           command: |
+            mkdir -p /testlogs
+            
             export OP_E2E_CANNON_ENABLED="<<parameters.cannon_enabled>>"
             # Note: We don't use circle CI test splits because we need to split by test name, not by package. There is an additional
             # constraint that gotestsum does not currently (nor likely will) accept files from different pacakges when building.
-            JUNIT_FILE=/tmp/test-results/<<parameters.module>>_<<parameters.target>>.xml make <<parameters.target>>
+            JUNIT_FILE=/tmp/test-results/<<parameters.module>>_<<parameters.target>>.xml make <<parameters.target>> 2>&1 | tee /testlogs/test.log
           working_directory: <<parameters.module>>
+      - store_artifacts:
+          path: /testlogs
+          when: always
       - store_test_results:
           path: /tmp/test-results