src: delete unreachable code in heap_utils.cc

PR-URL: #26815
Reviewed-By: Refael Ackermann <refack@gmail.com>

Author: gengjiawen

src/heap_utils.cc

@@ -280,15 +280,13 @@ class HeapSnapshotStream : public AsyncWrap,
 
   int DoShutdown(ShutdownWrap* req_wrap) override {
     UNREACHABLE();
-    return 0;
   }
 
   int DoWrite(WriteWrap* w,
               uv_buf_t* bufs,
               size_t count,
               uv_stream_t* send_handle) override {
     UNREACHABLE();
-    return 0;
   }
 
   bool IsAlive() override { return snapshot_ != nullptr; }