[kernel] Deprecates Db.Main

tests/libc/check_compliance.ml

tests/libc/check_const.ml

tests/libc/check_libc_anonymous_tags.ml

tests/libc/check_libc_naming_conventions.ml

tests/libc/check_parsing_individual_headers.ml

tests/misc/Debug_category.ml

tests/misc/add_assigns.ml

tests/misc/behavior_names.ml

tests/misc/bts0489.ml

tests/misc/bts1201.ml

tests/misc/bts1347.ml

tests/misc/bug_0209.ml

tests/misc/callsite.ml

tests/misc/change_main.ml

tests/misc/cil_builder.ml

tests/misc/cli_string_multiple_map.ml

tests/misc/copy_kf.ml

tests/misc/copy_machdep.ml

tests/misc/ensures.ml

tests/misc/find_enclosing_loop.ml