message: Do not CHECK fail for --num_run < 1.
  Setting --num_run=0 is useful to inspect VLOGs written during module compilation.
diff: @@ -174,6 +174,11 @@ StatusOr<Literal> ReplayComputation(const HloSnapshot& module,
  client->Compile(computation, argument_layouts, ExecutableBuildOptions())
  .ValueOrDie();
  + // Do not attmept to run the executable, if num_runs is less than 1.
  + if (opts.num_runs < 1) {
  + return Cancelled("Cancelled after compilation since --num_runs < 1.");
  + }
  +
  // Run the computation num_runs times, and return the result from the last
  // execution.
  StreamExecutorMemoryAllocator allocator(
  @@ -191,9 +196,6 @@ StatusOr<Literal> ReplayComputation(const HloSnapshot& module,
  << static_cast<double>(profile.compute_time_ns()) / 1e9 << "s";
  }
  - // Check that --num_runs > 0, otherwise *result below will fail with an
  - // unhelpful error (because the loop didn't run any iterations).
  - CHECK_GT(opts.num_runs, 0) << "--num_runs must be > 0";
  TF_ASSIGN_OR_RETURN(std::unique_ptr<Literal> result_literal,
  client->ShapedBufferToLiteral(*result));
  return std::move(*result_literal);
  