gradient accumulation tests, embeddings w pad_token fix, smaller models (#2059)

* add more test cases for gradient accumulation and fix zero3

* swap out for smaller model

* fix missing return

* fix missing pad_token in config

* support concurrency for multigpu testing

* cast empty deepspeed to empty string for zero3 check

* fix temp_dir as fixture so parametrize works properly

* fix test file for multigpu evals

* don't use default

* don't use default for fsdp_state_dict_type

* don't use llama tokenizer w smollm

* also automatically cancel multigpu for concurrency

.github/workflows/multi-gpu-e2e.yml

@@ -8,6 +8,11 @@ on:
   schedule:
     - cron: '0 0 * * 1,4'  # Runs at 00:00 UTC every monday & thursday
 
+# Cancel jobs on the same ref if a new one is triggered
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ github.ref != 'refs/heads/main' }}
+
 jobs:
   test-axolotl-multigpu:
     if: ${{ ! contains(github.event.commits[0].message, '[skip docker]]') && github.repository_owner == 'axolotl-ai-cloud' }}