external/boringssl: Sync to 348f0d8db9c2a0eca0503ba654020209c579d552.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/9bbdf5832de8a2d395303c669b594fc61c791f4d..348f0d8db9c2a0eca0503ba654020209c579d552

Test: BoringSSL CTS Presubmits.
Change-Id: I69a8590da0c89a0d66446775fd669e206a46308a
36 files changed