[LLVM-C] [OCaml] Remove LLVMAddBBVectorizePass

Summary: It was fully replaced back in 2014, and the implementation was removed 11 months ago by r306797.

Reviewers: hfinkel, chandlerc, whitequark, deadalnix

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D47436

llvm-svn: 333378