[eacsl:test] Update test oracles

...s/arith/oracle_ci/at_on-purely-logic-variables.res.oracle

.../tests/arith/oracle_ci/gen_at_on-purely-logic-variables.c

src/plugins/e-acsl/tests/arith/oracle_ci/gen_rationals.c

...s/e-acsl/tests/examples/oracle_ci/gen_functions_contiki.c

src/plugins/e-acsl/tests/memory/oracle_ci/gen_memsize.c