First commit of benchmarks for Catch runtime perf.

So far its very much a WIP with some problems that are known already and
not very representative tests.

scripts/runner.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python3
+
+import subprocess, os, sys
+import xml.etree.ElementTree as ET
+from collections import defaultdict
+from statistics import median, stdev
+from datetime import datetime
+
+def get_commit_hash():
+    res = subprocess.run('git rev-parse HEAD'.split(), check=True, stdout=subprocess.PIPE, universal_newlines=True)
+    return res.stdout.strip()
+
+if len(sys.argv) < 2:
+    print('Usage: {} benchmark-binary'.format(sys.argv[0]))
+    exit(1)
+
+
+num_runs = 10
+data = defaultdict(list)
+
+
+def parse_file(file):
+
+    def recursive_search(node):
+        if node.tag == 'TestCase':
+            results = node.find('OverallResult')
+            time = results.get('durationInSeconds')
+            data[node.get('name')].append(float(time))
+        elif node.tag in ('Group', 'Catch'):
+            for child in node:
+                recursive_search(child)
+
+    tree = ET.parse(file)
+    recursive_search(tree.getroot())
+
+def run_benchmarks(binary):
+    call = [binary] + '-d yes -r xml -o'.split()
+    for i in range(num_runs):
+        file = 'temp{}.xml'.format(i)
+        print('Run number {}'.format(i))
+        subprocess.run(call + [file])
+        parse_file(file)
+        # Remove file right after parsing, because benchmark output can be big
+        os.remove(file)
+
+
+# Run benchmarks
+run_benchmarks(sys.argv[1])
+
+result_file = '{:%Y-%m-%dT%H-%M-%S}-{}.result'.format(datetime.now(), get_commit_hash())
+
+
+print('Writing results to {}'.format(result_file))
+with open(result_file, 'w') as file:
+    for k in sorted(data):
+        file.write('{}: median: {} (s), stddev: {} (s)\n'.format(k, median(data[k]), stdev(data[k])))