As a follow-up to r235955, actually support up to 65535 arguments in a
subprogram. r235955 missed assembly support, having only tested the new
limit via C++ unit tests. Code patch by Amjad Aboud.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238854 91177308-0d34-0410-b5e6-96231b3b80d8
