Upcoming metadata changes in V8 6.8

[cjihrig]

• v8dbg_context_idx_closure
  • Renamed: v8dbg_context_idx_scope_info
  • V8 commit: v8/v8@39496a9#diff-f3f182b0510ba2ee39ae87e421ff110b

See nodejs/node-v8#60

[mmarchini]

If someone wants to work on this, I strongly suggest waiting for V8 6.8 branch cut (ETA: May 24th, 2018), because there might be other metadata changes until then.