This is based on personal tests with 1.11/1.12, and conversations with developers of core Julia. I did not try calling the function 70 times, but what used to crash immediately on jl_init() no longer does.
PackageCompiler should have (at least) the same limitations as regular Julia, so there isn’t anything to document there. The 1.12 change is part of some wider internal refactoring in the Julia compiler, but I’m afraid I cannot help you there.