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

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

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index 4862e986046f16bae1a7893d9bdb37adfef76349..4ee81a7486804efe72692542a32776562f997aaf 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -634,11 +634,6 @@ void VisitWordCompareZero(InstructionSelector* selector, Node* user,
 void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
                                       BasicBlock* fbranch) {
   FlagsContinuation cont(kNotEqual, tbranch, fbranch);
-  // If we can fall through to the true block, invert the branch.
-  if (IsNextInAssemblyOrder(tbranch)) {
-    cont.Negate();
-    cont.SwapBlocks();
-  }
   VisitWordCompareZero(this, branch, branch->InputAt(0), &cont);
 }