Cleared ResourceLoader blob store after update.php finishes.

Update.php is supposed to clear all localization caches. This
makes sure to clear the ResourceLoader's own message cache
as well.

Bug: 44524
Change-Id: I15ceb60f5e2e4d3ed9ba818fe6cd619f9adce5b2
Merge "Cleared ResourceLoader blob store after update.php finishes." into REL1_21