Remove special debug ExternalReferences.

src/mips/debug-mips.cc

Index: src/mips/debug-mips.cc
diff --git a/src/mips/debug-mips.cc b/src/mips/debug-mips.cc
index fcb5643d1572f4dedc58ddf5365f14c51fcc04e2..0ef9e29ddfb3605b8f2828a36064da10c224a970 100644
--- a/src/mips/debug-mips.cc
+++ b/src/mips/debug-mips.cc
@@ -155,8 +155,9 @@ static void Generate_DebugBreakCallHelper(MacroAssembler* masm,
   // Now that the break point has been handled, resume normal execution by
   // jumping to the target address intended by the caller and that was
   // overwritten by the address of DebugBreakXXX.
-  __ li(t9, Operand(
-      ExternalReference(Debug_Address::AfterBreakTarget(), masm->isolate())));
+  ExternalReference after_break_target =
+      ExternalReference::debug_after_break_target_address(masm->isolate());
+  __ li(t9, Operand(after_break_target));
   __ lw(t9, MemOperand(t9));
   __ Jump(t9);
 }