Add a pathfinding benchmark

Example run:

```
$ tools/build_and_run_benchmark.py path_benchmark

--------------------------------------------------------
Benchmark              Time             CPU   Iterations
--------------------------------------------------------
BM_SinglePath       2905 ns         2905 ns       240710
BM_Bridges         65521 ns        65519 ns         9845
BM_NoPath         147098 ns       147091 ns         4725
```

test/CMakeLists.txt

@@ -52,7 +52,9 @@ set(standalone_tests
 set(benchmarks
   clx_render_benchmark
   crawl_benchmark
-  dun_render_benchmark)
+  dun_render_benchmark
+  path_benchmark
+)
 
 include(Fixtures.cmake)
 
@@ -99,6 +101,7 @@ target_link_dependencies(format_int_test PRIVATE libdevilutionx_format_int langu
 target_link_dependencies(ini_test PRIVATE libdevilutionx_ini app_fatal_for_testing)
 target_link_dependencies(parse_int_test PRIVATE libdevilutionx_parse_int)
 target_link_dependencies(path_test PRIVATE libdevilutionx_pathfinding libdevilutionx_direction app_fatal_for_testing)
+target_link_dependencies(path_benchmark PRIVATE libdevilutionx_pathfinding app_fatal_for_testing)
 target_link_dependencies(str_cat_test PRIVATE libdevilutionx_strings)
 target_link_dependencies(utf8_test PRIVATE libdevilutionx_utf8)
 

test/path_benchmark.cpp

@@ -0,0 +1,122 @@
+#include <cstdint>
+
+#include <benchmark/benchmark.h>
+#include <utility>
+
+#include "engine/path.h"
+#include "engine/point.hpp"
+#include "engine/points_in_rectangle_range.hpp"
+#include "engine/size.hpp"
+
+namespace devilution {
+namespace {
+
+struct Map {
+	Size size;
+	const char *data;
+	char operator[](const Point &p) const { return data[p.y * size.width + p.x]; }
+};
+
+std::pair<Point, Point> FindStartDest(const Map &m)
+{
+	Point start, dest;
+	for (Point p : PointsInRectangle(Rectangle(Point { 0, 0 }, m.size))) {
+		switch (m[p]) {
+		case 'S':
+			start = p;
+			break;
+		case 'E':
+			dest = p;
+			break;
+		}
+	}
+	return { start, dest };
+}
+
+void BenchmarkMap(const Map &map, benchmark::State &state)
+{
+	const auto [start, dest] = FindStartDest(map);
+	const auto posOk = /*posOk=*/[&map](Point p) { return map[p] != '#'; };
+	for (auto _ : state) {
+		int8_t path[MaxPathLength];
+		int result = FindPath(/*canStep=*/[](Point, Point) { return true; },
+		    posOk, start, dest, path);
+		benchmark::DoNotOptimize(result);
+	}
+}
+
+void BM_SinglePath(benchmark::State &state)
+{
+	BenchmarkMap(
+	    Map {
+	        Size { 15, 15 },
+	        "###############"
+	        "#...#...#.....#"
+	        "#.#.#.#.#.###.#"
+	        "#S#...#.#.#...#"
+	        "#######.#.#.###"
+	        "##...##.#.#E..#"
+	        "#######.#.###.#"
+	        "###...#...#...#"
+	        "###.#######.###"
+	        "#...###...#...#"
+	        "#.#####.#.###.#"
+	        "#.#...#.#.#...#"
+	        "#.#.#.#.#.#.###"
+	        "#...#...#...###"
+	        "###############" },
+	    state);
+}
+
+void BM_Bridges(benchmark::State &state)
+{
+	BenchmarkMap(
+	    Map {
+	        Size { 15, 15 },
+	        "###############"
+	        "#.S...........#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "############.##"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "###.###########"
+	        "#.....E.......#"
+	        "###############" },
+	    state);
+}
+
+void BM_NoPath(benchmark::State &state)
+{
+	BenchmarkMap(
+	    Map {
+	        Size { 15, 15 },
+	        "###############"
+	        "#.S...........#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "#.............#"
+	        "###############"
+	        "#............E#"
+	        "###############" },
+	    state);
+}
+
+BENCHMARK(BM_SinglePath);
+BENCHMARK(BM_Bridges);
+BENCHMARK(BM_NoPath);
+
+} // namespace
+} // namespace devilution