Restore traversal context after enter / traverse (#13813)

benchmark/babel-core/real-case-preset-env-flow/babel-parser-expression.mjs

@@ -0,0 +1,42 @@
+import Benchmark from "benchmark";
+import baseline from "@babel-baseline/core";
+import current from "@babel/core";
+import parser from "@babel-baseline/parser";
+import { report } from "../../util.mjs";
+import { readFileSync } from "fs";
+
+const suite = new Benchmark.Suite();
+const fixtureName = "babel-parser-expression.txt";
+
+function createInput() {
+  return parser.parse(
+    readFileSync(new URL("./" + fixtureName, import.meta.url), {
+      encoding: "utf-8",
+    }),
+    { sourceType: "module", plugins: ["flow"] }
+  );
+}
+function benchCases(name, implementation, options) {
+  const input = createInput();
+  suite.add(
+    `${name} ${fixtureName}`,
+    () => {
+      implementation(input, {
+        plugins: ["@babel/preset-env", "@babel/preset-flow"],
+        targets: "ie 11",
+        configFile: false,
+        babelrc: false,
+        ...options,
+      });
+    },
+    {
+      // increase minSamples for accuracy
+      minSamples: 100,
+    }
+  );
+}
+
+benchCases("baseline", baseline.transformFromAstSync, {});
+benchCases("current", current.transformFromAstSync, {});
+
+suite.on("cycle", report).run();