fate-vc1_ilaced_twomv: use -flags +bitexact

Also updates the reference since it was generated by the non-bitexact
x86 specific code.
Merge commit '36f3aec3630f27df64f4ff2b52a1c9ced760eb52'

* commit '36f3aec3630f27df64f4ff2b52a1c9ced760eb52':
  fate-vc1_ilaced_twomv: use -flags +bitexact

Conflicts:
	tests/ref/fate/vc1_ilaced_twomv

See: 233d1acb7095b3dc89975cd4598c294cc4c08887
Merged-by: Michael Niedermayer <michaelni@gmx.at>
avcodec/on2avc: Check number of channels

Fixes out of array access
Fixes: asan_heap-oob_4da4f3_7_asan_heap-oob_4da4f3_173_Xmen_avc_500.vp6

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>