Resolve "ISM Metadata file too short for ltv testvectors for 3 and 4 ISMs"

Related to #528 (closed)

In case the ISM MD input file is shorter than the input audio file, the MD file is rewound and MD is read again from the beginning of the file. This logic also allows to specify MD file with a single line only in the case of static objects.

Note that the same logic is used in other reader utilities like FEC, head rotation, JBM, etc.

Non bit-exact operating points: none