Skip broken Tape Image records

[achaikou]

We saw several cases during recent LIS files investigation where declared PR record length doesn't match length of the data stored inside the TM, but TM.next correctly points to the start of the next correct PR.

As we disregard all Tape Headers information, we are unable to use this feature and fail.
But it looks like many utilities which investigate LIS files (Tape Verification Listings and similar) are able to read these files simply by skipping broken record and moving to the next TM.