[kernel] Move mach out of Cil_types

src/kernel_internals/runtime/machdep.ml

src/kernel_internals/runtime/machdep.mli

src/kernel_services/ast_data/cil_types.ml

src/kernel_services/ast_data/machine.ml

src/kernel_services/ast_data/machine.mli

src/kernel_services/ast_printing/cil_types_debug.ml

src/kernel_services/ast_printing/cil_types_debug.mli

src/kernel_services/ast_queries/cil.ml

src/kernel_services/ast_queries/cil_datatype.ml

src/kernel_services/ast_queries/cil_datatype.mli

src/kernel_services/ast_queries/file.ml

src/kernel_services/ast_queries/file.mli

tests/syntax/machdep_char_unsigned.ml