Revert "XCOMMONS-2029: Upgrade to Closure Compiler v20200920"
Revert "XCOMMONS-2029: Upgrade to Closure Compiler v20200920"

This reverts commit b9ac59aa5d0d39bfe289318669ea0eea4a7f54ee.

xwiki/xwiki-commons,xwiki/xwiki-commons