Revert r300964 + r300970 - [globalisel][tablegen] Import SelectionDAG's rule...

Revert r300964 + r300970 - [globalisel][tablegen] Import SelectionDAG's rule predicates and support the equivalent in GIRule.

It's causing llvm-clang-x86_64-expensive-checks-win to fail to compile and I
haven't worked out why. Reverting to make it green while I figure it out.

llvm-svn: 300978