[crankshaft] Generate lazy bailout point for HProlog instruction only when it is necessary.

src/crankshaft/mips/lithium-mips.cc

Index: src/crankshaft/mips/lithium-mips.cc
diff --git a/src/crankshaft/mips/lithium-mips.cc b/src/crankshaft/mips/lithium-mips.cc
index 015c1c43ecf02c6034a147453c98a5b4c449018d..ef478ff44dd1e52244ac0b9ad9295fa9819c929a 100644
--- a/src/crankshaft/mips/lithium-mips.cc
+++ b/src/crankshaft/mips/lithium-mips.cc
@@ -886,7 +886,7 @@ void LChunkBuilder::AddInstruction(LInstruction* instr,
   }
   chunk_->AddInstruction(instr, current_block_);
 
-  if (instr->IsCall() || instr->IsPrologue()) {
+  if (instr->IsCall()) {
     HValue* hydrogen_value_for_lazy_bailout = hydrogen_val;
     if (hydrogen_val->HasObservableSideEffects()) {
       HSimulate* sim = HSimulate::cast(hydrogen_val->next());
@@ -901,7 +901,11 @@ void LChunkBuilder::AddInstruction(LInstruction* instr,
 
 
 LInstruction* LChunkBuilder::DoPrologue(HPrologue* instr) {
-  return new (zone()) LPrologue();
+  LInstruction* result = new (zone()) LPrologue();
+  if (info_->num_heap_slots() > 0) {
+    result = MarkAsCall(result, instr);
+  }
+  return result;
 }