Deal with deoptimization duplications

[vivanishin]

Fix the FIXME in LLVMChunk::SetUpDeoptimizationData:

  // FIXME(llvm): This invariant fails when optimizer duplicates a deopt branch.
  CHECK_EQ(std::set<int>(sorted_ids.begin(), sorted_ids.end()).size(),
           sorted_ids.size());

This behavior manifests on zlib test from Octane benchmark.

Remove irrelevant loads from run.js and run

d8 --llvm-filter=a8 --noturbo-asm run.js 

There were other examples, but I don't have them at hand.