Fix locale matching algorithm for resources

We get ResTables two different ways: one is from AAPT, another from
settings-based requests from the Java side. In the settings-based
requests, localeScript will be autocomputed, but for AAPT-filled
tables (especially if they come from older versions of AAPT), we need
to compute the script.

Previously, locales that came from packages were incorrectly assumed
to have "undeterminable" scripts, rather than "undetermined" scripts.
This led to us mistakenly falling back to the old logic of requiring
the locales' countries to match, rather than just looking at computed
scripts.

Bug: 27157452

Change-Id: Id7e346d3ecfb17273ffb63de5bcb4849a6eafbbd