[turbofan] Rework handling of loop exits in loop peeling.

src/compiler/loop-analysis.cc

Index: src/compiler/loop-analysis.cc
diff --git a/src/compiler/loop-analysis.cc b/src/compiler/loop-analysis.cc
index 17e4fd40aef535c78b59207fc9d1563fd82bfb75..d52c7c7742df51f2a679f2a2897332b895bcaf1a 100644
--- a/src/compiler/loop-analysis.cc
+++ b/src/compiler/loop-analysis.cc
@@ -18,10 +18,6 @@ namespace compiler {
 #define BIT(x) (1u << OFFSET(x))
 #define INDEX(x) ((x) >> 5)
 
-// TODO(titzer): don't assume entry edges have a particular index.
-static const int kAssumedLoopEntryIndex = 0;  // assume loops are entered here.
-
-
 // Temporary information for each node during marking.
 struct NodeInfo {
   Node* node;