Upgrade BoringSSL

[jonasfj]

We need to upgrade BoringSSL, however, their build scripts have changed a bit. In particular how ASM files are added, so we might need to make some changes.

The logic is in:
https://github.com/google/webcrypto.dart/blob/master/tool/update-boringssl.py

We need to bump BORINGSSL_REVISION.

And then fix our build script generator logic, since asm_outputs parameter isn't give to WriteFiles anymore.

I tried playing with this, but we need to do more than simple remove the asm_outputs parameter.

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There is some documentation in: https://boringssl.googlesource.com/boringssl/+/refs/heads/master/INCORPORATING.md

The rest is reading BoringSSL code and build system 🤣