Test for RelativeDateTimeFormatter apostrophe bug.

Add a test for a bug in ICU RelativeDateTimeFormatter.combineDateAndTime
which led to single-quotes that were meant to quote characters appearing
in the output.

The relevant code used SimpleFormatterImpl for performance reasons
previously, but that class does not consider ' to be a quoting character
and just copies them into the output. In this patch we use MessageFormat
to handle the pattern instead which handles the single quote as desired.

See http://bugs.icu-project.org/trac/ticket/13295 and
http://unicode.org/cldr/trac/ticket/10321 for context and a potential
long-term fix.

Bug: 63745717
Test: libcore.icu.RelativeDateTimeFormatterTest
Change-Id: Iab0b902ab381ee1239d7304daed1cf53702c53f7
1 file changed