[NFC] Remove obsolete simplifyOnceImpl function

The function simplifyOnce only calls simplifyOnceImpl and does nothing else.
Having this separate helper makes no sense. Removing it.

Patch by Dmitry Bakunevich!

Differential Revision: https://reviews.llvm.org/D112517
Reviewed By: mkazantsev
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 84bf364..848c8a0 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -280,7 +280,6 @@
   }
 
   bool simplifyOnce(BasicBlock *BB);
-  bool simplifyOnceImpl(BasicBlock *BB);
   bool run(BasicBlock *BB);
 
   // Helper to set Resimplify and return change indication.
@@ -6680,7 +6679,7 @@
   return false;
 }
 
-bool SimplifyCFGOpt::simplifyOnceImpl(BasicBlock *BB) {
+bool SimplifyCFGOpt::simplifyOnce(BasicBlock *BB) {
   bool Changed = false;
 
   assert(BB && BB->getParent() && "Block not embedded in function!");
@@ -6760,12 +6759,6 @@
   return Changed;
 }
 
-bool SimplifyCFGOpt::simplifyOnce(BasicBlock *BB) {
-  bool Changed = simplifyOnceImpl(BB);
-
-  return Changed;
-}
-
 bool SimplifyCFGOpt::run(BasicBlock *BB) {
   bool Changed = false;