[file_packager] Remove redundant isNode check

This was added back in #22802 but seems redundant since the check
just below for the indexedDB global should be enough to handle the
node case.

Split out from #24883

Author: sbc100

tools/file_packager.py

@@ -805,13 +805,7 @@ def generate_js(data_target, data_files, metadata):
         var DB_VERSION = 1;
         var METADATA_STORE_NAME = 'METADATA';
         var PACKAGE_STORE_NAME = 'PACKAGES';
-        function openDatabase(callback, errback) {'''
-      if options.support_node:
-        code += '''
-            if (isNode) {
-              return errback();
-            }'''
-      code += '''
+        function openDatabase(callback, errback) {
           if (typeof indexedDB == 'undefined') {
             throw 'using IndexedDB to cache data can only be done on a web page or in a web worker';
           }