Revert "Change the dyld notification function that lldb puts a breakpoint in"

This reverts commit c3192196.

Reverting my second attempt at https://reviews.llvm.org/D139453
changing which dyld notification method is being used.
The Intel macOS CI bot is still failing with this
rewrite at https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake/
I'll need to set up an Intel macOS system running a matching
OS version to debug this directly I think.