CppunitTest_sw_ooxmlsdrexport: move all AlternateContent tests

AlternateContent is used while dealing with shapes, move all those
tests. With this, the original suite has 330 asserts, the new one has
78, and they can run in parallel since
2efee3c632bb8372685bb9f7b07e99b91668d779.

Toplevel 'make' on my machine:
- before: 3m15.237s
- after:  2m40.197s

Change-Id: Id7ac9708e29ae8c6ea7db8aa845de089ed4bdf42