Remove default case from switch in DependentCode::DependencyGroupName.

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index b6e0eaca94a8871cc780adea4225941fb672709c..d7753a71cc05f0fccf24fc73d0478230ae3f63db 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11677,10 +11677,11 @@ const char* DependentCode::DependencyGroupName(DependencyGroup group) {
       return "allocation-site-tenuring-changed";
     case kAllocationSiteTransitionChangedGroup:
       return "allocation-site-transition-changed";
-    default:
-      UNREACHABLE();
-      return "?";
+    case kGroupCount:
+      break;  // Enum count, not a valid group value.
   }
+  UNREACHABLE();
+  return "?";
 }