An acquired $MFT stream had no reader, so an analyst holding one could only
treat it as an opaque file. Recognize the FILE signature of the first record
and inventory every record's header: sequence number, flags, used and total
bytes, base record reference and update-sequence array.
Each record's update-sequence fixups are verified against its sector
trailers. A mismatch keeps the header facts, is reported on the record and is
counted in the metadata, so a record that was not cleanly written is visible
rather than silently accepted. A missing or short array is reported as
unverified, a wrong signature stops the scan at its offset, and a trailing
partial record is reported as a byte count. Attributes, filenames and the
$UsnJrnl:$J journal are not decoded, so no path or change history is claimed.
Part of #9867
(cherry picked from commit ccb45f5712)