[v6.x] deps: backport 071b655 from V8 upstream

Original commit message:

[PATCH] [debugger] Scope iterator should not visit inner function literals.

R=marja@chromium.org
BUG=chromium:621361

Review-Url: https://codereview.chromium.org/2185913003
Cr-Commit-Position: refs/heads/master@{#38087}

Fixes: https://github.com/nodejs/node/issues/15075

/cc @nodejs/v8 @hashseed

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)

V8