[turbofan] Clean up and factor out branch generation logic.

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index ce7ce56616522b995dc51ce5ce3a1091556ad33c..1115506477bbcfba75d5a39d123a47614822bd58 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -899,12 +899,6 @@ void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
 
   FlagsContinuation cont(kNotEqual, tbranch, fbranch);
 
-  // If we can fall through to the true block, invert the branch.
-  if (IsNextInAssemblyOrder(tbranch)) {
-    cont.Negate();
-    cont.SwapBlocks();
-  }
-
   // Try to combine with comparisons against 0 by simply inverting the branch.
   while (CanCover(user, value)) {
     if (value->opcode() == IrOpcode::kWord32Equal) {