Improve benchmark scripts (#299)

Author: dduan

.gitignore

@@ -13,3 +13,4 @@ tmp
 Docs
 Package.resolved
 .benchmarkBaselines
+.benchmarkWorktrees

Scripts/benchmark.sh

@@ -1,18 +1,5 @@
 #!/bin/bash
 set -euo pipefail
 
-export TOMLDECODER_BENCHMARKS=1
-
-baseline=$(git rev-parse "$1")
-target=$(git rev-parse "$2")
-
-if [ -d ".benchmarkBaselines/TOMLDecoderBenchmarks/$baseline" ]; then
-    echo "Reusing baseline for $baseline"
-else
-    git checkout "$baseline"
-    swift package -c release --allow-writing-to-package-directory \
-        benchmark baseline update "$baseline" --grouping metric
-fi
-
-git checkout "$target"
-swift package -c release benchmark baseline compare "$baseline"
+./Scripts/benchmark_run.sh "$@" >&2
+./Scripts/benchmark_report.sh "$@"