noexec: consolidate code

noexec: consolidate code

function                                             old     new   delta
run_noexec_applet_and_exit                             -      61     +61
find_applet_by_name                                  128     124      -4
run_applet_no_and_exit                               441     434      -7
tryexec                                              169     152     -17
pseudo_exec_argv                                     338     321     -17
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/6 up/down: 61/-48)             Total: 13 bytes

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