fix(grunt): Add platforms folder to produced NPM package (#6015)

gruntfile.js

@@ -236,6 +236,11 @@ module.exports = function(grunt) {
                 ],
                 dest: localCfg.outDir + "/"
             },
+            platformsFiles: {
+                expand: true,
+                src: "tns-core-modules/platforms/**/*.*",
+                dest: localCfg.outDir + "/"
+            },
             apps: {
                 expand: true,
                 src: copyAppsSrc,
@@ -321,6 +326,7 @@ module.exports = function(grunt) {
     // Register Tasks
     grunt.registerTask("collect-modules-raw-files", [
         "copy:jsLibs",
+        "copy:platformsFiles",
         "copy:license"
     ]);