tests/check/elements/: It's "endianness", not "endianess". Fixes unit tests.

tests/check/elements/: It's "endianness", not "endianess". Fixes unit tests.

Original commit message from CVS:
* tests/check/elements/rganalysis.c: (test_buffer_const_float_mono),
(test_buffer_const_float_stereo), (test_buffer_const_int16_mono),
(test_buffer_const_int16_stereo), (test_buffer_square_float_mono),
(test_buffer_square_float_stereo), (test_buffer_square_int16_mono),
(test_buffer_square_int16_stereo):
* tests/check/elements/rglimiter.c: (create_test_buffer):
* tests/check/elements/rgvolume.c: (test_buffer_new):
It's "endianness", not "endianess". Fixes unit tests.