[Eva] In abstract domains, update can return Bottom.

src/plugins/value/domains/abstract_domain.mli

src/plugins/value/domains/apron/apron_domain.ok.ml

src/plugins/value/domains/cvalue/cvalue_domain.ml

src/plugins/value/domains/cvalue/cvalue_transfer.ml

src/plugins/value/domains/domain_builder.ml

src/plugins/value/domains/domain_product.ml

src/plugins/value/domains/equality/equality_domain.ml

src/plugins/value/domains/gauges/gauges_domain.ml

src/plugins/value/domains/inout_domain.ml

src/plugins/value/domains/offsm_domain.ml

src/plugins/value/domains/simple_memory.ml

src/plugins/value/domains/symbolic_locs.ml

src/plugins/value/domains/unit_domain.ml

src/plugins/value/engine/transfer_stmt.ml

src/plugins/value/register.ml