Add simple benchmark scripts

tests/benchmarks/run-benchmarks.sh

@@ -0,0 +1,24 @@
+if ! which hyperfine > /dev/null 2>&1; then
+    echo "'hyperfine' does not seem to be installed."
+    echo "You can get it here: https://github.com/sharkdp/hyperfine"
+    exit 1
+fi
+
+echo "### Startup time"
+echo
+
+hyperfine --warmup 3 bat
+
+echo
+echo "### Plain text"
+echo
+
+hyperfine --warmup 3 "bat --language txt --paging=never 'test-src/jquery-3.3.1.js'"
+
+echo
+echo "### Time to syntax-highlight large files"
+echo
+
+for SRC in test-src/*; do
+    hyperfine --warmup 3 "bat --style=full --color=always --paging=never '$SRC'"
+done