blocks_compressed.js generated by Gulp has bugs

[alienzhangyw]

Describe the bug

The blocks_compressed.js generated by Gulp has a few differences to the one in the original release. When I use it to open demos (eg. code demo), all the blocks which have extensions or mutators are not loaded, and I get errors on the browser console.

To Reproduce

Steps to reproduce the behavior:

1. npm install
2. npm run build
3. Open the code demo
4. See error

Expected behavior

The compressed files generated by Gulp work fine as the original ones.

Screenshots

Desktop (please complete the following information):

• OS: windows10 1909
• Browser Edge/Chrome
• Version Edge 18/Chrome 78

Stack Traces

SCRIPT445: SCRIPT445: Object doesn't support this action
blockly_compressed.js (230,495)

40: Object doesn't support this action
blockly_compressed.js (229,494)

70: Unable to get property 'length' of undefined or null reference
blocks_compressed.js (92,369).

[alienzhangyw]

I'm going to make some new blocks, but I can't use build.py in China due to the network issue. So I tried to test build with gulp. Files were built but got errors in use.