Delete should return false if an element doesn't exist in a set.
ECMA_VALUE_EMPTY wasn't checked in case of a deleted property.
JerryScript-DCO-1.0-Signed-off-by: Daniel Balla dballa@inf.u-szeged.hu
Also implement the missing iterator initializer part from the Map builtin object constructor.
JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu