Add an INSIST to check that the number of days in a month is sane
We use a hard-coded const
array with the number of days for each
month, however Coverity reports a false-positive warning that
days[i] * 86400
can overflow a 32 bits signed integer.
INSIST should add an additional safety check, which an optimizing compiler can safely remove, and which should make some sensitive static code analyzers happy.
Closes #3154 (closed)