swift234

Revert "Revert r14430: Create two SILLinking steps, one before Diagnostics for transparent functions and the other after Diagnostics for non transparent functions if -sil-link-all is passed in."

This recommits r14446 with necessary changes.

The problem was that after my change SILGen was dumped before sil linking
occured. This change adds back in the code to ensure that sil linking occurs.

Swift SVN r14455