remove unnecessary strict helper

src/babel/transformation/helpers/strict.js

@@ -1,19 +0,0 @@
-import * as t from "../../types";
-
-export function has(node) {
-  var first = node.body[0];
-  return t.isExpressionStatement(first) && t.isLiteral(first.expression, { value: "use strict" });
-}
-
-export function wrap(node, callback) {
-  var useStrictNode;
-  if (has(node)) {
-    useStrictNode = node.body.shift();
-  }
-
-  callback();
-
-  if (useStrictNode) {
-    node.body.unshift(useStrictNode);
-  }
-}

src/babel/transformation/transformers/internal/module-formatter.js

@@ -1,19 +1,15 @@
-import * as strict from "../../helpers/strict";
-
 export var metadata = {
   group: "builtin-modules"
 };
 
 export var Program = {
   exit(program, parent, scope, file) {
-    strict.wrap(program, function () {
+    // ensure that these are at the top, just like normal imports
-      // ensure that these are at the top, just like normal imports
+    for (var node of (file.dynamicImports: Array)) {
-      for (var node of (file.dynamicImports: Array)) {
+      node._blockHoist = 3;
-        node._blockHoist = 3;
+    }
-      }
 
-      program.body = file.dynamicImports.concat(program.body);
+    program.body = file.dynamicImports.concat(program.body);
-    });
 
     if (!file.transformers["es6.modules"].canTransform()) return;