Visit the landingpad instruction.

Visit the landingpad instruction.

This generates the correct SDNodes for the landingpad instruction. It makes an
assumption that the result of the landingpad instruction has at least two
values. And that the first value is a pointer to the exception object and the
second value is the "selector."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136430 91177308-0d34-0410-b5e6-96231b3b80d8