Update to run tests with 4 nodes to reduce infra load (cloudfoundry#3681)

This PR optimizes the integration test execution in CI to reduce infrastructure load and improve test reliability.

This change splits the integration-tests-full-ci Makefile target into 3 sequential batches instead of running all 6 test suites together with high parallelism. Additionally, the number of parallel nodes is reduced from 12 to 4 in the GitHub Actions workflow.

Test suites are now grouped logically into batches that run sequentially with controlled parallelism to prevent infrastructure overload while maintaining reasonable test execution time.

Author: anujc25

.github/workflows/tests-integration-reusable.yml

@@ -18,7 +18,7 @@ on:
 
 env:
   ENV_NAME: ${{ inputs.env-name }}
-  NODES: 12
+  NODES: 4
   FLAKE_ATTEMPTS: ${{ vars.TEST_FLAKE_ATTEMPTS || '5' }}
   BBL_CLI_VERSION: ${{ vars.BBL_CLI_VERSION }}
   BOSH_CLI_VERSION: ${{ vars.BOSH_CLI_VERSION }}

Makefile

@@ -140,9 +140,13 @@ integration-full-tests: integration-tests-full
 integration-tests-full: build integration-cleanup integration-isolated integration-push integration-experimental integration-plugin integration-global integration-selfcontained ## Run all isolated, push, experimental, plugin, selfcontained, and global integration tests
 
 integration-tests-full-ci: install-test-deps integration-cleanup
-	$(ginkgo_int) -nodes $(NODES) \
-		integration/shared/isolated integration/v7/isolated integration/shared/plugin integration/shared/experimental integration/v7/experimental integration/v7/push
-	$(ginkgo_int) integration/shared/global integration/v7/global
+	$(ginkgo_int) -nodes $(NODES) -flake-attempts $(FLAKE_ATTEMPTS) \
+		integration/shared/isolated integration/v7/isolated
+	$(ginkgo_int) -nodes $(NODES) -flake-attempts $(FLAKE_ATTEMPTS) \
+		integration/shared/plugin integration/shared/experimental
+	$(ginkgo_int) -nodes $(NODES) -flake-attempts $(FLAKE_ATTEMPTS) \
+		integration/v7/experimental integration/v7/push
+	$(ginkgo_int) -flake-attempts $(FLAKE_ATTEMPTS) integration/shared/global integration/v7/global
 
 lint: format ## Runs all linters and formatters
 	@echo "Running linters..."