hush: implement "return NUM in trap sets $? after trap"

function                                             old     new   delta
builtin_return                                        47      67     +20
check_and_run_traps                                  243     259     +16
run_pipe                                            1583    1597     +14
hush_main                                           1076    1086     +10
run_list                                            1054    1055      +1
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(add/remove: 0/0 grow/shrink: 5/0 up/down: 61/0)               Total: 61 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
13 files changed