Investigate changes in SERVER-56728: Cannot run 4.9+ on Apple Silicon

Description

Description of Linked Ticket

Mongo 4.9+ cannot start on M1 laptops:

% /tmp/mms-automation/test/versions/mongodb-macos-x86_64-4.9.0-rc0/bin/mongod

zsh: illegal hardware instruction  /tmp/mms-automation/test/versions/mongodb-macos-x86_64-4.9.0-rc0/bin/mongod

acm tracked down that this is because the ISA targeting for the server build was upgraded in 4.9 to sandybridge, which uses AVX instructions that are not handled by Rosetta:
https://developer.apple.com/documentation/apple-silicon/about-the-rosetta-translation-environment

Rosetta translates all x86_64 instructions, but it doesn't support the execution of some newer instruction sets and processor features, such as AVX, AVX2, and AVX512 vector instructions.

He recommended special case downgrading the macOS target ISA to something that doesn’t generate AVX until we have a native Apple Silicon build.

Scope of changes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)