Allow disk reads when context creates LocaleConfig

ContextImpl needs to create a LocaleConfig so resources has access to it
for multilocale. This can cause disk reads which cause a strict mode
violation because it happens on the UI thread. This temporary allows it
on the UI thread just around that read.

Fixes: 309232726
Test: manual
Change-Id: I9e1ad21a19bbbdbe6b2fff78489f43e291babad1