Use a better means of avoiding simultaneous test runs locally

Author: HoloRin

user-template.bazelrc

@@ -8,7 +8,7 @@ build --//:elixir_home=/Users/rabbitmq/.kiex/elixirs/elixir-1.12.0/lib/elixir
 build --spawn_strategy=local
 
 # run one test at a time on the local machine
-build --test_strategy=exclusive
+build --local_test_jobs=1
 
 # don't re-run flakes automatically on the local machine
 build --flaky_test_attempts=1