Always initialize the debugger eagerly.

src/ia32/debug-ia32.cc

Index: src/ia32/debug-ia32.cc
diff --git a/src/ia32/debug-ia32.cc b/src/ia32/debug-ia32.cc
index 563199b82d9a3f09d242fb1ca7232fdff7daa41a..e7a7b6058153dddef621cb93de2af35e5d0cec8f 100644
--- a/src/ia32/debug-ia32.cc
+++ b/src/ia32/debug-ia32.cc
@@ -25,7 +25,7 @@ void BreakLocationIterator::SetDebugBreakAtReturn() {
   ASSERT(Assembler::kJSReturnSequenceLength >=
          Assembler::kCallInstructionLength);
   rinfo()->PatchCodeWithCall(
-      debug_info_->GetIsolate()->debug()->debug_break_return()->entry(),
+      debug_info_->GetIsolate()->builtins()->Return_DebugBreak()->entry(),
       Assembler::kJSReturnSequenceLength - Assembler::kCallInstructionLength);
 }
 
@@ -56,7 +56,7 @@ void BreakLocationIterator::SetDebugBreakAtSlot() {
   ASSERT(IsDebugBreakSlot());
   Isolate* isolate = debug_info_->GetIsolate();
   rinfo()->PatchCodeWithCall(
-      isolate->debug()->debug_break_slot()->entry(),
+      isolate->builtins()->Slot_DebugBreak()->entry(),
       Assembler::kDebugBreakSlotLength - Assembler::kCallInstructionLength);
 }