ARM: remove custom jump table UID

ARM: remove custom jump table UID

We were creating and propagating two separate indices for each jump table (from
back in the mists of time). However, the generic index used by other backends
is sufficient to emit a unique symbol so this was unneeded.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237294 91177308-0d34-0410-b5e6-96231b3b80d8