Add --print-benchmarking-metrics to the VM for Golem.

runtime/vm/flag_list.h

Index: runtime/vm/flag_list.h
diff --git a/runtime/vm/flag_list.h b/runtime/vm/flag_list.h
index c59746ece95f07868f414f125ea51628447170a5..856a7a7d472463b49a3a13ad8776d7b012637441 100644
--- a/runtime/vm/flag_list.h
+++ b/runtime/vm/flag_list.h
@@ -123,6 +123,8 @@
   P(precompiled_mode, bool, false, "Precompilation compiler mode")             \
   C(precompiled_runtime, true, false, bool, false, "Precompiled runtime mode") \
   P(print_snapshot_sizes, bool, false, "Print sizes of generated snapshots.")  \
+  P(print_benchmarking_metrics, bool, false,                                   \
+    "Print additional memory and latency metrics for benchmarking.")           \
   R(print_ssa_liveranges, false, bool, false,                                  \
     "Print live ranges after allocation.")                                     \
   C(print_stop_message, false, false, bool, false, "Print stop message.")      \