Use test secrets in e2e workflow

[zhongkechen]

Summary

• assume the e2e test role from TEST_ROLE_ARN
• constrain AWS credentials to TEST_ACCOUNT_ID
• pass TEST_LAMBDA_EXECUTION_ROLE_ARN to SAM for Lambda execution roles
• pass TEST_ACCOUNT_ID into cloud tests so generated function ARNs target the test account
• publish a per-Java-version workflow run summary of Surefire test cases
• name e2e stacks and functions with a Java{Version}- prefix instead of a -java{version}-runtime suffix
• run cloud e2e test methods/classes in parallel with fixed JUnit parallelism of 4
• skip local tests during SAM's Maven build by setting MAVEN_OPTS in the sam build step

Refs #520

Testing

• mvn spotless:apply
• git diff --check
• YAML parse check
• python3 -c 'import ast, pathlib; ast.parse(pathlib.Path(".github/scripts/publish_e2e_test_summary.py").read_text())'
• JAVA_VERSION=17 GITHUB_STEP_SUMMARY=/private/tmp/e2e-summary-test.md python3 ../.github/scripts/publish_e2e_test_summary.py
• sam validate --template-file template.yaml
• mvn -pl examples -am test -Dtest=InvokeExampleTest,RetryInvokeExampleTest -Dsurefire.failIfNoSpecifiedTests=false
• mvn -pl examples -am test -Dtest=CloudBasedIntegrationTest,OtelXRayIntegrationTest -Dtest.cloud.enabled=false -Djunit.jupiter.execution.parallel.enabled=true -Djunit.jupiter.execution.parallel.mode.default=concurrent -Djunit.jupiter.execution.parallel.mode.classes.default=concurrent -Djunit.jupiter.execution.parallel.config.strategy=fixed -Djunit.jupiter.execution.parallel.config.fixed.parallelism=4 -Dsurefire.failIfNoSpecifiedTests=false