[kernel] introduce status flag for acsl-extensions

src/kernel_internals/typing/mergecil.ml

src/kernel_services/ast_data/cil_types.mli

src/kernel_services/ast_data/property.ml

src/kernel_services/ast_printing/cil_printer.ml

src/kernel_services/ast_printing/cil_types_debug.ml

src/kernel_services/ast_printing/description.ml

src/kernel_services/ast_queries/cil.ml

src/kernel_services/ast_queries/cil_datatype.ml

src/kernel_services/ast_queries/file.ml

src/kernel_services/ast_queries/filecheck.ml

src/kernel_services/ast_queries/logic_const.ml

src/kernel_services/ast_queries/logic_const.mli

src/kernel_services/ast_queries/logic_typing.ml

src/kernel_services/ast_queries/logic_typing.mli

src/kernel_services/ast_queries/logic_utils.ml

src/plugins/gui/design.ml

src/plugins/gui/filetree.ml

src/plugins/metrics/metrics_cilast.ml

src/plugins/value/slevel/per_stmt_slevel.ml

src/plugins/value/utils/unroll_annots.ml