Delete CodeInit and CodeRecTy from TableGen.

The code type was always identical to a string anyway. Now it is simply
a synonym. The code literal syntax [{...}] is still valid.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148092 91177308-0d34-0410-b5e6-96231b3b80d8
5 files changed