Add a test for KxmlSerializer attributes with whitespace chars.

Delete some unused Kxml classes while I'm in the area, and
combine our two classes named KXmlSerializerTest.

(cherry-pick of 22a12704190060f74e308a5b5aa32d0b7f715183.)

Change-Id: Id8b3f72edc58547e49ad86c51a171dce3669be3f
6 files changed