Revert "Compute base addresses from program headers while reading /proc/self/maps."

This reverts commit 6f903f3a228bc8e10cd7bda76342954feb3000c5.

Reason for revert: https://build.chromium.org/p/chromium.linux/builders/Android%20Clang%20Builder%20%28dbg%29/builds/104887

Original change's description:
> Compute base addresses from program headers while reading /proc/self/maps.
> 
> This cherry picks this glog change:
> https://github.com/google/glog/pull/261
> with a reimplementation of the program header reading logic for the
> sandboxed symbolizer.
> 
> This should cause unsymbolized stack traces to contain the correct
> addresses for binaries linked with lld.
> 
> Bug: 772559
> Change-Id: Ief9cbb463b3b4c32149da893c89c2eefd76b05d4
> Reviewed-on: https://chromium-review.googlesource.com/752753
> Commit-Queue: Peter Collingbourne <pcc@chromium.org>
> Reviewed-by: Mark Mentovai <mark@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#513956}

TBR=ukai@chromium.org,pcc@chromium.org,mark@chromium.org

Change-Id: Ie02672bcfb2d28729530d61975083ba2187efd4e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 772559
Reviewed-on: https://chromium-review.googlesource.com/753864
Reviewed-by: Sky Malice <skym@chromium.org>
Commit-Queue: Sky Malice <skym@chromium.org>
Cr-Commit-Position: refs/heads/master@{#513978}

• base/debug/proc_maps_linux.h[diff]
• base/debug/stack_trace_posix.cc[diff]
• base/third_party/symbolize/README.chromium[diff]
• base/third_party/symbolize/symbolize.cc[diff]