Merge #17267: bench: Fix negative values and zero for -evals flag

3bb0a4674f bench: Fix negative values and zero for -evals flag (nijynot)

Pull request description:

  This PR makes `bench_bitcoin -evals=0` evaluate at once and throws when `-evals` is a negative integer.

  ---

  Currently when you run `bench_bitcoin -evals=0`, it'll get stuck at
  ```
  # Benchmark, evals, iterations, total, min, max, median
  ```
  . This is not intuitively expected and should instead evaluate instantly as it's set to zero. Negative integers for `-evals` does not make sense either and should throw if set.

ACKs for top commit:
  laanwj:
    ACK 3bb0a4674f

Tree-SHA512: 03cd4c7c55134c7ffd8cdb6ee993551ce41061a73e13c3c047247af9df1fd7ed07d798272b643ec864099036922aaadbdcd2b798d710406f48df60b9d5448c26

src/bench/bench_bitcoin.cpp

@@ -51,6 +51,13 @@ int main(int argc, char** argv)
     std::string scaling_str = gArgs.GetArg("-scaling", DEFAULT_BENCH_SCALING);
     bool is_list_only = gArgs.GetBoolArg("-list", false);
 
+    if (evaluations == 0) {
+        return EXIT_SUCCESS;
+    } else if (evaluations < 0) {
+        tfm::format(std::cerr, "Error parsing evaluations argument: %d\n", evaluations);
+        return EXIT_FAILURE;
+    }
+
     double scaling_factor;
     if (!ParseDouble(scaling_str, &scaling_factor)) {
         tfm::format(std::cerr, "Error parsing scaling factor as double: %s\n", scaling_str.c_str());