GH-131372: only install build-details.json in the main install

[FFY00]

• Issue: build-details.json should be installed to different locations for nondebug/debug builds and have distinct base_interpreter values #131372

[ned-deily]

@FFY00 I just noticed all those cat commands being used for install steps and, without looking further into it, I wonder if those might be opening up some security issues. Typically, we use the install utility which does ensure specific permissions etc on installed files, something cat would not do.

[FFY00]

cat is only reading the build directory location here, install still does all the actual file touching.

That said, I really don't like this ideom. It has been around for a while, but unfortunately it's not easy to get rid of. I attempted it in GH-131761, but haven't had time to follow it through.

[ned-deily]

cat is only reading the build directory location here, install still does all the actual file touching.

D'oh, sorry for the noise!

[mgorny]

This change makes no sense to me. IIUC the difference between altinstall and install was only that the latter additionally installed python and python3 symlinks. These are undesirable to distributions that support multiple Python versions and handle switching themselves, hence we use altinstall. I don't see why build-details.json that is installed inside the directory for a single Python version would be controlled by the same knob.