* Commit the fix (by Chris) for a tblgen type inferencing bug.

* Commit the fix (by Chris) for a tblgen type inferencing bug.
* Enhanced tblgen to handle instructions which have chain operand and writes a
chain result.
* Enhanced tblgen to handle instructions which produces no results. Part of
the change is a temporary hack which relies on instruction property (e.g.
isReturn, isBranch). The proper fix would be to change the .td syntax to
separate results dag from ops dag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24587 91177308-0d34-0410-b5e6-96231b3b80d8