external/boringssl: Sync to a93bc1124c00b1ac0a68ea5cb14b158d6c8366e1.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/3120950b1e27635ee9b9d167052ce11ce9c96fd4..a93bc1124c00b1ac0a68ea5cb14b158d6c8366e1

Test: BoringSSL CTS Presubmits.
Change-Id: Ifa05098e38da1872f2fe043a10780e91cbd3315c
24 files changed