Revert "[SLP]Fix PR69196: Instruction does not dominate all uses"

This reverts commit 8e2b2c4 to fix
a crash reported in https://lab.llvm.org/buildbot/#/builders/230/builds/19993.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -11214,7 +11214,7 @@ Value *BoUpSLP::vectorizeTree(
     TE->VectorizedValue = nullptr;
     auto *UserI =
         cast<Instruction>(TE->UserTreeIndices.front().UserTE->VectorizedValue);
-    Builder.SetInsertPoint(UserI);
+    Builder.SetInsertPoint(PrevVec);
     Builder.SetCurrentDebugLocation(UserI->getDebugLoc());
     Value *Vec = vectorizeTree(TE);
     PrevVec->replaceAllUsesWith(Vec);