Add gzdecode fallback to GlobalFunctions

* Follows-up I6383e933b.
* Replaced existing usage of `gzinflate( substr( $data, 10, -8 ) );`
  with `gzdecode( $data )`.

Change-Id: Ie2916584f92ff72c7d7ddca73acf1c94dda38cca
Merge "Add gzdecode fallback to GlobalFunctions"