ci: Validate the experiment that retries failed tests in a new process

Signed-off-by: Rémy Coutable <remy@rymai.me>

.gitlab-ci.yml

@@ -93,6 +93,7 @@ variables:
   CHECK_PRECOMPILED_ASSETS: "true"
   FF_USE_FASTZIP: "true"
   SKIP_FLAKY_TESTS_AUTOMATICALLY: "true"
+  RETRY_FAILED_TESTS_IN_NEW_PROCESS: "true"
   # Run with decomposed databases by default
   DECOMPOSED_DB: "true"
 

doc/development/pipelines.md

@@ -187,7 +187,7 @@ See the [experiment issue](https://gitlab.com/gitlab-org/quality/team-tasks/-/is
 
 #### Automatic retry of failing tests in a separate process
 
-When the `$RETRY_FAILED_TESTS_IN_NEW_PROCESS` variable is set to `true`, RSpec tests that failed are automatically retried once in a separate
+Unless `$RETRY_FAILED_TESTS_IN_NEW_PROCESS` variable is set to `false` (`true` by default), RSpec tests that failed are automatically retried once in a separate
 RSpec process. The goal is to get rid of most side-effects from previous tests that may lead to a subsequent test failure.
 
 We keep track of retried tests in the `$RETRIED_TESTS_REPORT_FILE` file saved as artifact by the `rspec:flaky-tests-report` job.