[debugger] fix step-next for tail calls.

src/assembler.h

Index: src/assembler.h
diff --git a/src/assembler.h b/src/assembler.h
index 46566ffe6f1f8b6fbf51d0b4b7534e2c138816ab..192d16b64d7ba8613d90b4b4ab7369426c0d7dde 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -398,6 +398,7 @@ class RelocInfo {
     DEBUG_BREAK_SLOT_AT_POSITION,
     DEBUG_BREAK_SLOT_AT_RETURN,
     DEBUG_BREAK_SLOT_AT_CALL,
+    DEBUG_BREAK_SLOT_AT_TAIL_CALL,
 
     EXTERNAL_REFERENCE,  // The address of an external C++ function.
     INTERNAL_REFERENCE,  // An address inside the same function.
@@ -491,7 +492,7 @@ class RelocInfo {
   }
   static inline bool IsDebugBreakSlot(Mode mode) {
     return IsDebugBreakSlotAtPosition(mode) || IsDebugBreakSlotAtReturn(mode) ||
-           IsDebugBreakSlotAtCall(mode);
+           IsDebugBreakSlotAtCall(mode) || IsDebugBreakSlotAtTailCall(mode);
   }
   static inline bool IsDebugBreakSlotAtPosition(Mode mode) {
     return mode == DEBUG_BREAK_SLOT_AT_POSITION;
@@ -502,6 +503,9 @@ class RelocInfo {
   static inline bool IsDebugBreakSlotAtCall(Mode mode) {
     return mode == DEBUG_BREAK_SLOT_AT_CALL;
   }
+  static inline bool IsDebugBreakSlotAtTailCall(Mode mode) {
+    return mode == DEBUG_BREAK_SLOT_AT_TAIL_CALL;
+  }
   static inline bool IsDebuggerStatement(Mode mode) {
     return mode == DEBUGGER_STATEMENT;
   }