[eacsl:codegen] Add tests for variables in switch tracking

src/plugins/e-acsl/known_bugs/decl_in_switch.c

src/plugins/e-acsl/tests/bts/bts1386_complex_flowgraph.c

src/plugins/e-acsl/tests/bts/issue-eacsl-91.c

.../tests/bts/oracle_ci/bts1386_complex_flowgraph.res.oracle

...-acsl/tests/bts/oracle_ci/gen_bts1386_complex_flowgraph.c

src/plugins/e-acsl/tests/bts/oracle_ci/gen_issue-eacsl-91.c

...gins/e-acsl/tests/bts/oracle_ci/issue-eacsl-91.res.oracle

...tests/bts/oracle_dev/bts1386_complex_flowgraph.res.oracle

...ins/e-acsl/tests/bts/oracle_dev/issue-eacsl-91.res.oracle

src/plugins/e-acsl/tests/memory/decl_in_switch.c

...s/e-acsl/tests/memory/oracle_ci/decl_in_switch.err.oracle

...s/e-acsl/tests/memory/oracle_ci/decl_in_switch.res.oracle

...lugins/e-acsl/tests/memory/oracle_ci/gen_decl_in_switch.c

.../e-acsl/tests/memory/oracle_dev/decl_in_switch.res.oracle