MAGETWO-32371: Move jsonEncode and jsonDecode from core helper to framework

- Removed Magento\Core\Helper\Data

Author: Joan He

app/code/Magento/Core/Helper/Data.php

@@ -792,6 +792,7 @@
     ['Mage_Core_Model_Config_System'],
     ['Mage_Core_Model_Design_Source_Apply'],
     ['Mage_Core_Model_Language'],
+    ['Magento\Core\Helper\Data'],
     ['Magento\Core\Model\Flag', 'Magento\Framework\Flag'],
     ['Magento\Framework\Model\Exception', 'Magento\Framework\Exception\LocalizedException'],
     ['Magento\Core\Model\AbstractModel', 'Magento\Framework\Model\AbstractModel'],

dev/tests/static/testsuite/Magento/Test/Legacy/_files/obsolete_classes.php

@@ -721,6 +721,8 @@
     ['isVerbose', 'Magento\Framework\Shell'],
     ['isWindowsOs', 'Magento\TestFramework\Helper\Memory'],
     ['joinTaxClass', 'Magento\Tax\Helper\Data'],
+    ['jsonDecode', 'Magento\Core\Helper\Data', 'Magento\Framework\Json\Helper\Data::jsonDecode'],
+    ['jsonEncode', 'Magento\Core\Helper\Data', 'Magento\Framework\Json\Helper\Data::jsonEncode'],
     ['load', 'Magento\Core\Model\Layout\Update', 'Magento\Framework\View\Model\Layout\Merge'],
     ['loadBaseContents', 'Magento\Email\Model\Template'],
     ['loadBase', 'Magento\Core\Model\Config'],