[TI removal] Remove TerminatorInst references from bindings.

For the Go bindings, this just removes the no longer useful "isa"-style
wrapper. If there is a user that is interested, they can add a wrapper
for `Instruction::isTerminator`.

For the OCaml bindings, this is just a documentation update.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344726 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed