deps: upgrade v8 to 4.2.77.15

This includes the out-of-tree patch (but fixed in upstream HEAD) from
commit 41c00a2 ("deps: enable v8 postmortem debugging again".)

PR-URL: https://github.com/iojs/io.js/pull/1399


Reviewed-By: Fedor Indutny <fedor@indutny.com>