swresample: do not put multiple statements in one line

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
swresample/resample: fix invert_initial_buffer() after flush

Fixes: asan_heap-uaf_2071250_7_139.ogg
Fixes: assertion failure
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>