Snapshotted from 5e7fd50e17 in the
upstream repository:
https://github.com/google/googletest

Since standalone builds and bots will need this, checking in a copy
rather than require everyone use gclient, repo, git submodules or scary
CMake scripts is probably simplest.

Consumers with their own copies of googletest will likely wish to ignore
or even exclude this directory.

BUG=129

Change-Id: If9f4cec5ae0d7a3976dcfffd1ead6950ef7b7c4e
Reviewed-on: https://boringssl-review.googlesource.com/13229
Reviewed-by: David Benjamin <davidben@google.com>