Reapply [mlir][vector] Refactor WarpOpScfForOp to support unused or swapped forOp results.

[charithaintc]

Reapply attempt for : #148291
Fix for the build failure reported in : https://lab.llvm.org/buildbot/#/builders/116/builds/15477

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This crash is caused by mismatch of distributed type returned by getDistributedType and intended distributed type for forOp results.

Solution diff: 20c2cf6

Example:

func.func @warp_scf_for_broadcasted_result(%arg0: index) -> vector<1xf32> {
  %c128 = arith.constant 128 : index
  %c1 = arith.constant 1 : index
  %c0 = arith.constant 0 : index
  %2 = gpu.warp_execute_on_lane_0(%arg0)[32] -> (vector<1xf32>) {
    %ini = "some_def"() : () -> (vector<1xf32>)
    %0 = scf.for %arg3 = %c0 to %c128 step %c1 iter_args(%arg4 = %ini) -> (vector<1xf32>) {
      %1 = "some_op"(%arg4) : (vector<1xf32>) -> (vector<1xf32>)
      scf.yield %1 : vector<1xf32>
    }
    gpu.yield %0 : vector<1xf32>
  }
  return %2 : vector<1xf32>
}

In this case the distributed type for forOp result is vector<1xf32> (result is not distributed and broadcasted to all lanes instead). However, in this case getDistributedType will return NULL type.

Therefore, if the distributed type can be recovered from warpOp, we should always do that first before using getDistributedType

[charithaintc]

Hi, @kurapov-peter, @Jianhui-Li Can you please review the diff here.
20c2cf6

[kurapov-peter]

I'd cover all the indexing logic with assertions, pretty brittle.