fate: aac: Add test for AAC-LD
fate: Increase the tolerance in the lavr tests

A few fate instances on OS/2, OpenBSD, FreeBSD and IA64 linux currently
still fail a few tests with a maxdiff of 6.

Signed-off-by: Martin Storsjö <martin@martin.st>
wtv: Seek by sector properly

Use an helper function to seek by sector to avoid possible mistakes
due shifting by WTV_SECTOR_BITS a 32bit integer.

Contrary to common intuition, a 32 bit integer left shifted
by a 64 bit integer does not promote the 32 bit integer to
64 bit before shifting.