remove dead indexing code (csarofeen#1806)

Author: shmsong

build_variables.bzl

@@ -658,7 +658,6 @@ libtorch_cuda_core_sources = [
     "torch/csrc/jit/codegen/cuda/grouped_reduction.cpp",
     "torch/csrc/jit/codegen/cuda/index_compute.cpp",
     "torch/csrc/jit/codegen/cuda/lower_index_compute.cpp",
-    "torch/csrc/jit/codegen/cuda/index_reference_replay.cpp",
     "torch/csrc/jit/codegen/cuda/instrumentation.cpp",
     "torch/csrc/jit/codegen/cuda/ir_base_nodes.cpp",
     "torch/csrc/jit/codegen/cuda/ir_builder.cpp",