Verify NARROW_FORMAT integration to SimpleDataFormat.java against 8u121-b13 (part 2)

Integrate NARROW_FORMAT filtering logic in getDisplayNamesMap(),
effectively making NARROW_FORMAT handling up-to-date with 8u121-b13.
This introduces behavior change: months in narrow format can't be
parsed in some locales which have all months names unique (e.g. AK).

Added a test case that asserts that months in narrow format can't
be parsed for both all-distinct months names and not (AK and UK
locales respectively).

This CL contains a test case that demonstrates this behavior change,
and is a partial verification CL (i.e. not completes SimpleDateFormat
verification).

Bug: 66411240
Test: cts-tradefed run cts -m CtsLibcoreTestCases --abi arm64-v8a
Change-Id: I5db8178e312a37cbedfe2ca5ee381f2436a03978