Causes a clang crash (see crbug.com/1457256). This reverts commit 015049338d7e8e0e81f2ad2f94e5a43e2e3f5220.
Differential Revision: https://reviews.llvm.org/D137872
The previous assertion was relatively easy to trigger, and likely will be easy to trigger going forward. EmitDelegateCallArg is relatively popular. This cleanly diagnoses PR28299 while I work on a proper solution. llvm-svn: 348991