Fix plugin loading cache (#14576)

tests/integration/__tests__/plugin-cache.js

@@ -0,0 +1,21 @@
+import prettier from "../../config/prettier-entry.js";
+
+// #13235
+test("Plugin instance should not cached", async () => {
+  expect([
+    await prettier.format(".", {
+      plugins: [
+        { parsers: { baz: { parse: () => ({}), astFormat: "baz-ast" } } },
+        { printers: { "baz-ast": { print: () => "1" } } },
+      ],
+      parser: "baz",
+    }),
+    await prettier.format(".", {
+      plugins: [
+        { parsers: { baz: { parse: () => ({}), astFormat: "baz-ast" } } },
+        { printers: { "baz-ast": { print: () => "2" } } },
+      ],
+      parser: "baz",
+    }),
+  ]).toEqual(["1", "2"]);
+});