Check memory usage when emulating x86 images on M1/M2 macs

When cross compiling the 0.12.10 x86 image on ARM64 macs, the `RUSTFLAGS='-C link-arg=-s' cargo build --release` step in the builder image required a lot of RAM. 20 GB was not enought but 25 GB worked.

For maintaining this repository this is fine. However, I wonder what the users of rust-optimizer/workspace-optimizer have to configure when using the resulting image. We need to measure this (test a few settings with a few contracts) and document it.

It is likely the memory consumtion of the Rust compiler changed between 0.12.10 (Rust 1.65.0) and 0.12.9 (Rust 1.64.0).