Revert "[SLP] Support memory runtime alias checks"

This reverts commit 96a53b1 to fix
buildbots https://lab.llvm.org/buildbot/#/builders/223/builds/7209
reported in llvm/llvm-project#209305

Reviewers: 

Pull Request: llvm/llvm-project#209793

Author: alexey-bataev

llvm/include/llvm/Transforms/Vectorize/SLPVectorizer.h

@@ -172,25 +172,12 @@ struct SLPVectorizerPass : public OptionalPassInfoMixin<SLPVectorizerPass> {
                                           unsigned Idx, unsigned MinVF,
                                           unsigned &Size);
 
-  /// Single vectorization attempt for a store chain. \p vectorizeStoreChain
-  /// wraps this to retry once with runtime alias checks enabled when the
-  /// normal attempt is blocked only by runtime-checkable may-alias
-  /// dependencies.
-  std::optional<bool> vectorizeStoreChainImpl(ArrayRef<Value *> Chain,
-                                              slpvectorizer::BoUpSLP &R,
-                                              unsigned Idx, unsigned MinVF,
-                                              unsigned &Size);
-
   bool vectorizeStores(
       ArrayRef<StoreInst *> Stores, slpvectorizer::BoUpSLP &R,
       DenseSet<std::tuple<Value *, Value *, Value *, Value *, unsigned>>
           &Visited,
       bool AllowMaskedStores = true);
 
-  /// Set by runImpl() when runtime alias check versioning changed the CFG, so
-  /// run() can drop CFG-analysis preservation only when necessary.
-  bool CFGChanged = false;
-
   /// The store instructions in a basic block organized by base pointer.
   StoreListMap Stores;