Enforce inherent limitations of dos and dvh partition table formats.

Enforce inherent limitations of dos and dvh partition table formats.

* libparted/disk.c (_check_partition): Enforce the 32-bit limitation
on a partition's starting sector number and length (in sectors).
With the usual 512-byte sector size, this limits the maximum
partition size to just under 2TB.
(_partition_max_start, _partition_max_len): New functions.
(_check_partition): Use them.
* tests/t4100-msdos-partition-limits.sh: New file.  Test vs. msdos.
* tests/t4100-dvh-partition-limits.sh: New file.  Test vs. dvh.
* tests/Makefile.am (TESTS): Add t4100-msdos-partition-limits.sh
and t4100-dvh-partition-limits.sh.