tests/check/: Add unit tests for wavpack elements (#352476).

tests/check/: Add unit tests for wavpack elements (#352476).

Original commit message from CVS:
Patch by: Sebastian Dröge <slomo at circular-chaos.org>
* tests/check/Makefile.am:
* tests/check/elements/.cvsignore:
* tests/check/elements/wavpackdec.c: (setup_wavpackdec),
(cleanup_wavpackdec), (GST_START_TEST), (wavpackdec_suite), (main):
* tests/check/elements/wavpackenc.c: (setup_wavpackenc),
(cleanup_wavpackenc), (GST_START_TEST), (wavpackenc_suite), (main):
* tests/check/elements/wavpackparse.c: (wavpackparse_found_pad),
(setup_wavpackparse), (cleanup_wavpackparse), (GST_START_TEST),
(wavpackparse_suite), (main):
Add unit tests for wavpack elements (#352476).