Don't emit calls to virtual [[noreturn]] functions as noreturn; overrides of a
[[noreturn]] function are not required to also be [[noreturn]]. We still emit
calls to virtual __attribute__((noreturn)) functions as noreturn; unlike GCC,
we do require overriders to also be noreturn for that attribute.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176476 91177308-0d34-0410-b5e6-96231b3b80d8