scsi-disk: improve the lba-out-of-range tests for read/write/verify

Improve the tests for the LBA to cover more cases.

For the 16 byte opcodes, the lba is a uint64, so we need to check is to
make sure that we do not wrap.  For example if an opcode would specify
the LBA:0xffffffffffffffff and LEN:2 then lba+len would wrap to 1.

Also verify that ALL requested blocks are available, not just the first one.

Signed-off-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
