Port QDir to qsizetype [2/3]: implementation

Port ints that should be qsizetype. None of these are likely to cause
bugs, because both path lengths and number of directory entries are
usually limited by the OS, not by INT_MAX.

As a drive-by, replace length() with size() and port some functions
from QString to QStringView.

Pick-to: 6.4 6.3 6.2
Task-number: QTBUG-103525
Change-Id: I79eb6d580631346a1e77eb1c7a73a3880943794e
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

0 files changed, 0 insertions, 0 deletions