tests/swr: move the results out of the functions

This prevents all results from being declared whenever the function is called.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
tests: Add ac3_fixed decoder test

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
tests: add adpcm trellis tests

adpcm_ima_qt does not produce reproducible results, so it is temporarily
disabled (see #3701).

Signed-off-by: Timothy Gu <timothygu99@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>