analyzer: use 'final' and 'override' where appropriate

analyzer: use 'final' and 'override' where appropriate

gcc/analyzer/ChangeLog:
	* call-info.cc: Add "final" and "override" to all vfunc
	implementations that were missing them, as appropriate.
	* engine.cc: Likewise.
	* region-model.cc: Likewise.
	* sm-malloc.cc: Likewise.
	* supergraph.h: Likewise.
	* svalue.cc: Likewise.
	* varargs.cc: Likewise.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>