AITER backend extension and workload optimizations (#6838)

Co-authored-by: wunhuang <wunhuang@amd.com>
Co-authored-by: Hubert Lu <Hubert.Lu@amd.com>

test/srt/test_nightly_gsm8k_eval_amd.py

@@ -171,7 +171,7 @@ class TestNightlyGsm8KEval(unittest.TestCase):
                     os.environ["HF_HUB_DISABLE_XET"] = (
                         "1" if model in DISABLE_HF_XET_MODELS else "0"
                     )
-                    os.environ["SGLANG_AITER_MOE"] = (
+                    os.environ["SGLANG_USE_AITER"] = (
                         "0" if model in TRITON_MOE_MODELS else "1"
                     )