* Upstream Chromium local changes to symbolize.cc

Chromium has its own fork of symbolize.cc and symbolize.h, and it has
several not-yet-upstreamed changes, that are not specific to Chromium.

This patch upstreams such a changes.

  Fixed google::FindSymbol reading past end of a section
  https://chromium.googlesource.com/chromium/src/+/3dae0a2d7da309159a301e40a592692ec8431a38

  Fix -INT_MIN integer overflow in itoa_r().
  https://chromium.googlesource.com/chromium/src/+/ac4d28e9cb934e01ff16a9e67a5f387caa82719f

  Add print_unsymbolized_stack_traces gn arg.
  https://chromium.googlesource.com/chromium/src/+/6a2726776f59cdcf0090f584a15db4a1ab8c40d7

  Switch to standard integer types in base/.
  https://chromium.googlesource.com/chromium/src/+/9b6f42934e5a1e65ebfc668d91a28a6e2678a14c

* Add a build option to print unsymbolized traces

This PRINT_UNSYMBOLIZED_STACK_TRACES option to cmake, and
--enable-unsymbolized-traces option to autoconf.