Using the WS_VSCROLL style causes the ES_AUTOVSCROLL option to be set,
and using the WS_HSCROLL style causes the ES_AUTOHSCROLL flag to be
set (except with richedit v1.0).

user32/tests: Add support for testing only some bits of wparam or lparam. Make some more messages optional.

comdlg32: If a measurement system isn't specified use the default one and update the Flags field to reflect this.

This gives a minor performance improvement.

Based on a patch by Mike Ruprecht.