Switch back to supported CI runners (#887)

Author: ZainRizvi

.github/workflows/float8_test.yml

@@ -22,7 +22,7 @@ jobs:
       matrix:
         include:
           - name: SM-89
-            runs-on: amz2023.linux.g6.4xlarge.experimental.nvidia.gpu
+            runs-on: linux.g6.4xlarge.experimental.nvidia.gpu
             torch-spec: '--pre torch --index-url https://download.pytorch.org/whl/nightly/cu121'
             gpu-arch-type: "cuda"
             gpu-arch-version: "12.1"