[ci] Deprecate original CI template (vllm-project#5624)

Signed-off-by: kevin <[email protected]>

Author: khluu

.buildkite/test-pipeline.yaml

@@ -1,6 +1,6 @@
 # In this file, you can add more tests to run either by adding a new step or
 # adding a new command to an existing step. See different options here for examples.
-# This script will be feed into Jinja template in `test-template.j2` to generate
+# This script will be feed into Jinja template in `test-template-aws.j2` to generate
 # the final pipeline yaml file.
 
 steps: