Backport BreakIterator::refreshInputText to icu4c 4.8.

Corresponds to these two patches:

1. http://bugs.icu-project.org/trac/changeset/30145
2. http://bugs.icu-project.org/trac/changeset/30201

For icu4c bug http://bugs.icu-project.org/trac/ticket/8490.

(cherry-pick of 0745c569f807bddcfc8d9f21eba504955fcdba98.)

Bug: 7288264
Bug: 7307154
Change-Id: Ice80d53c2f5722bb24ad841a943252b41b97cfa6
8 files changed