hadrian: Don't read package environments in ghc-stage1 wrapper

The stage1 compiler may be on the brink of existence and not have even a working base library. You may have installed packages globally with a similar stage2 compiler which will then lead to arguments such as --show-iface not even working because you are passing too many package flags. The solution is simple, don't read these implicit files.

Fixes #21803 (closed)