Uprev //base/third_party/symbolize

This CL update //base/third_party/symbolize to the latest version by
copying upstream symbolize.{h,cc} and demangle.{h,cc} as-is, so
that google::Symbolize() gets thread-safe.

//sandbox change is needed to allow pread() used by symbolize.cc.
This should be safe since we already allow lseek() and read().

Bug: 904743
Change-Id: I50b8389dfa18175e8c734c26440f651f74e6daa4
Reviewed-on: https://chromium-review.googlesource.com/c/1334991
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Derek Schuff <dschuff@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Taiju Tsuiki <tzik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613679}
15 files changed