Go bindings: remove contextless metadata bindings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224175 91177308-0d34-0410-b5e6-96231b3b80d8
Go bindings: expose the Metadata type.

Also modifies SetCurrentDebugLocation to take individual arguments rather
than an MDNode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224176 91177308-0d34-0410-b5e6-96231b3b80d8
Go bindings: introduce Metadata.ReplaceAllUsesWith.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224177 91177308-0d34-0410-b5e6-96231b3b80d8
Go bindings: introduce llvm.TemporaryMDNode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224178 91177308-0d34-0410-b5e6-96231b3b80d8
Go bindings: introduce Value.ConstantAsMetadata.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224179 91177308-0d34-0410-b5e6-96231b3b80d8