testsuite/: s/gst_pad_new/&_from_template/ prepare deprecation of gst_pad_new

testsuite/: s/gst_pad_new/&_from_template/ prepare deprecation of gst_pad_new

Original commit message from CVS:
* testsuite/bytestream/gstbstest.c: (gst_bstest_init):
* testsuite/dynparams/dparamstest.c: (gst_dptest_init):
* testsuite/refcounting/pad.c: (main):
* testsuite/refcounting/thread.c: (create_thread_ghostpads):
s/gst_pad_new/&_from_template/
prepare deprecation of gst_pad_new