[memory-model] fix bug #1715 occuring because __memory_size was not declared ghost

src/plugins/e-acsl/doc/Changelog

src/plugins/e-acsl/share/e-acsl/memory_model/e_acsl_mmodel.h

...ins/e-acsl/tests/e-acsl-runtime/oracle/empty.1.res.oracle

...ugins/e-acsl/tests/e-acsl-runtime/oracle/empty.res.oracle

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_addrOf.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_addrOf2.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_alias.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_alias2.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_arith.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_arith2.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_array.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_array2.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_at.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_at2.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_bts1304.c

...plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_bts13042.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_bts1307.c

...plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_bts13072.c

src/plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_bts1324.c

...plugins/e-acsl/tests/e-acsl-runtime/oracle/gen_bts13242.c