Use Array#findLastIndex (#16384)

scripts/build/transform/transforms/index.js

@@ -1,11 +1,13 @@
 import transformArrayFindLast from "./transform-array-find-last.js";
+import transformArrayFindLastIndex from "./transform-array-find-last-index.js";
 import transformObjectHasOwnCall from "./transform-object-has-own.js";
 import transformRelativeIndexing from "./transform-relative-indexing.js";
 import transformStringReplaceAll from "./transform-string-replace-all.js";
 
 export default [
+  transformArrayFindLast,
+  transformArrayFindLastIndex,
   transformObjectHasOwnCall,
   transformRelativeIndexing,
   transformStringReplaceAll,
-  transformArrayFindLast,
 ];

scripts/build/transform/transforms/transform-array-find-last-index.js

@@ -0,0 +1,13 @@
+import createMethodCallTransform from "./create-method-call-transform.js";
+
+const transformArrayFindLastIndex = createMethodCallTransform({
+  methodName: "findLastIndex",
+  argumentsLength: 1,
+  functionName: "__arrayFindLastIndex",
+  functionImplementationUrl: new URL(
+    "../../shims/array-find-last-index.js",
+    import.meta.url,
+  ),
+});
+
+export default transformArrayFindLastIndex;