Fix test failures due to unexpected overload resolution

Starting with Ie04e8a27050849fee1c93ef14b9944acc70fafe4,
CursorAnchorInfo#getComposingText() returns CharSequence rather
than String.  This causes unexpected overload resolution,
which results in test failures.

BUG: 15088391
Change-Id: I51e2b23573e92be7e5b1dcca6402e85364408215
1 file changed