message: Remove unused `hasSingleNonZeroAt` function (NFC)
  Fix clang warning.
diff: @@ -610,21 +610,6 @@ static void addOrderingConstraints(const FlatAffineConstraints &srcDomain,
  }
  }
  -// Returns true if 'isEq' constraint in 'dependenceDomain' has a single
  -// non-zero coefficient at (rowIdx, idPos). Returns false otherwise.
  -// TODO(andydavis) Move this function to FlatAffineConstraints.
  -static bool hasSingleNonZeroAt(unsigned idPos, unsigned rowIdx, bool isEq,
  - FlatAffineConstraints *dependenceDomain) {
  - unsigned numCols = dependenceDomain->getNumCols();
  - for (unsigned j = 0; j < numCols - 1; ++j) {
  - int64_t v = isEq ? dependenceDomain->atEq(rowIdx, j)
  - : dependenceDomain->atIneq(rowIdx, j);
  - if ((j == idPos && v == 0) || (j != idPos && v != 0))
  - return false;
  - }
  - return true;
  -}
  -
  // Computes distance and direction vectors in 'dependences', by adding
  // variables to 'dependenceDomain' which represent the difference of the IVs,
  // eliminating all other variables, and reading off distance vectors from
  