Swift Calling Convention: Parameters are allowed after the
swift_error/swift_context parameter

We need to be able to decelare witness functions which append the self type and
the self witness tables at the end of the parameter list.

rdar://28720996

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@283933 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 00d311a51369c41efbdae2e4935713fa10bb0e91)
3 files changed