Revert "Merge pull request #23331 from zbraniecki/1022767-use-json-l10n-manifests"

This reverts commit 2d16dbb66bc1acdf759e3ad43e5ac9c4c9f9aa2c, reversing
changes made to 001d1761e4685c2a08d3e96bb362f031d47f4033.
Bug 1052486: Call UIManager.initTZ later, giving the mobile network more time to connect. r=achen