[KERNEL32]

[KERNEL32]
GetNextVDMCommand function:
- Avoid using deep nested levels of indentation.
- Fix the error check conditions (+ status value) for the CsrClientCallServer call to make it compatible with what windows' basesrv can return to us.

[BASESRV]
- Remove some useless "NTAPI" from functions.
- Factor out some code used for creating and destroying console records, and for the destruction of the pair of event handles.
- Use "IsListEmpty" when needed.
- Fix BaseSrvFillCommandInfo so that it returns the needed lengths (even if the user-given lengths are zero) and set the expected status error in case the buffer lenghts are too small (not STATUS_BUFFER_TOO_SMALL but STATUS_INVALID_PARAMETER because it's what kernel32 error check expects, for windows compat; see above).
- Fix initialization of new DOS records: no need to create a new one if there is one already free (status VDM_READY).
- Fix the loop that searches for a valid DOS record containing command information available as well as the conditions in which case our caller needs to wait in GetNextVDMCommand call.

NOTE: The internal state flags of the DOS records have normally nothing to do with the VDM state flags we report back to the user.

CORE-8247 CORE-9711 CORE-9773

svn path=/trunk/; revision=69201