[debugger] fix step-next for tail calls.

src/assembler.cc

Index: src/assembler.cc
diff --git a/src/assembler.cc b/src/assembler.cc
index 6bcd2fef291f4d66a4bf9ce1c1a7268dfd9f69d4..0ca865bdd0f4a552f693cf67b38879940c807b18 100644
--- a/src/assembler.cc
+++ b/src/assembler.cc
@@ -838,6 +838,8 @@ const char* RelocInfo::RelocModeName(RelocInfo::Mode rmode) {
       return "debug break slot at return";
     case DEBUG_BREAK_SLOT_AT_CALL:
       return "debug break slot at call";
+    case DEBUG_BREAK_SLOT_AT_TAIL_CALL:
+      return "debug break slot at tail call";
     case CODE_AGE_SEQUENCE:
       return "code age sequence";
     case GENERATOR_CONTINUATION:
@@ -936,6 +938,7 @@ void RelocInfo::Verify(Isolate* isolate) {
     case DEBUG_BREAK_SLOT_AT_POSITION:
     case DEBUG_BREAK_SLOT_AT_RETURN:
     case DEBUG_BREAK_SLOT_AT_CALL:
+    case DEBUG_BREAK_SLOT_AT_TAIL_CALL:
     case GENERATOR_CONTINUATION:
     case WASM_MEMORY_REFERENCE:
     case NONE32: