Even without --trace-gc dump the last few GC messages on OOM

src/heap/gc-tracer.h

Index: src/heap/gc-tracer.h
diff --git a/src/heap/gc-tracer.h b/src/heap/gc-tracer.h
index 7fb6a766a6037181758eebd67eadaaa8f23b8bef..d3f3455358c52152164dab3e72187a0935d76598 100644
--- a/src/heap/gc-tracer.h
+++ b/src/heap/gc-tracer.h
@@ -420,6 +420,10 @@ class GCTracer {
   // TODO(ernstm): Move to Heap.
   void Print() const;
 
+  // Prints a line and also adds it to the heap's ring buffer so that
+  // it can be included in later crash dumps.
+  void Output(const char* format, ...) const;
+
   // Compute the mean duration of the events in the given ring buffer.
   double MeanDuration(const EventBuffer& events) const;