Abstract out fetching of break_address in debug mode

src/mips/assembler-mips.h

Index: src/mips/assembler-mips.h
diff --git a/src/mips/assembler-mips.h b/src/mips/assembler-mips.h
index 2ba3ef7166f2f9023adb77c5d128dd12a51768bc..dfaac9baa37cf7934e0e1fbd66167be509fa2e23 100644
--- a/src/mips/assembler-mips.h
+++ b/src/mips/assembler-mips.h
@@ -511,6 +511,9 @@ class Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   static void JumpLabelToJumpRegister(Address pc);
 
   static void QuietNaN(HeapObject* nan);