[shardformer]delete xformers (#5859)

* delete xformers

* fix

* fix

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

colossalai/shardformer/policies/bloom.py

@@ -11,14 +11,13 @@ import colossalai.shardformer.layer as col_nn
 from ..modeling.bloom import (
     BloomPipelineForwards,
     build_bloom_alibi_tensor_fn,
-    get_bloom_flash_attention_forward,
     get_bloom_sequence_parallel_forward_fn,
     get_jit_fused_bloom_attention_forward,
     get_jit_fused_bloom_gelu_forward,
     get_jit_fused_bloom_mlp_forward,
     get_lm_forward_with_dist_cross_entropy,
 )
-from ..modeling.jit import get_dropout_add_func, get_jit_fused_dropout_add_func, get_jit_fused_gelu_forward_func
+from ..modeling.jit import get_jit_fused_dropout_add_func, get_jit_fused_gelu_forward_func
 from .base_policy import ModulePolicyDescription, Policy, SubModuleReplacementDescription
 
 
@@ -165,16 +164,6 @@ class BloomPolicy(Policy):
                 target_key=BloomModel,
             )
 
-        if self.shard_config.enable_flash_attention:
-            self.append_or_create_method_replacement(
-                description={
-                    "forward": get_bloom_flash_attention_forward(),
-                    "dropout_add": get_dropout_add_func(),
-                },
-                policy=policy,
-                target_key=BloomAttention,
-            )
-
         # enable jit fused operator
         if self.shard_config.enable_jit_fused:
             self.append_or_create_method_replacement(