automation/eclair_analysis: substitute deprecated service STD.emptrecd

automation/eclair_analysis: substitute deprecated service STD.emptrecd

The ECLAIR service STD.emptrecd (which checks for empty structures) is being
deprecated; hence, as a preventive measure, STD.anonstct (which checks for
structures with no named members, an UB in C99) is used here; the latter being
a more general case than the previous one, this change does not affect the
analysis. This new service is already supported by the current version of
ECLAIR.

No functional change.

Signed-off-by: Nicola Vetrini <nicola.vetrini@bugseng.com>
Acked-by: Julien Grall <jgrall@amazon.com>