This change reverts #5617, because it will require extensive testing that will take up more time than we have before the next scheduled release.
Reverting this change does not mean we are abandoning it. We aim to pick it back up once there's a sufficient time window to allow for testing on multiple distros running a mixture of OpenSSL 1.x and 3.x.
This change updates OpenSSL from 1.1.1w to 3.5.2. The code works as-is, but many functions have been marked as deprecated and thus will need to be rewritten. For now we explicitly add the `-DOPENSSL_SUPPRESS_DEPRECATED` to give us time to do so, while providing us with the benefits of the updated version.
* Copy Antithesis SDK version 0.4.0 to directory external/
* Add build option `voidstar` to enable instrumentation with Antithesis SDK
* Define instrumentation macros ASSERT and UNREACHABLE in terms of regular C assert
* Replace asserts with named ASSERT or UNREACHABLE
* Add UNREACHABLE to LogicError
* Document instrumentation macros in CONTRIBUTING.md
