sim/nsh: add nxevent into nsh demo

1. add nxevent into nsh demo
2. enable ostest

Signed-off-by: chao an <anchao@lixiang.com>

Author: anchao

boards/sim/sim/sim/configs/nsh/defconfig

@@ -53,10 +53,12 @@ CONFIG_PSEUDOFS_ATTRIBUTES=y
 CONFIG_PSEUDOFS_SOFTLINKS=y
 CONFIG_READLINE_TABCOMPLETION=y
 CONFIG_SCHED_BACKTRACE=y
+CONFIG_SCHED_EVENTS=y
 CONFIG_SCHED_HAVE_PARENT=y
 CONFIG_SCHED_WAITPID=y
 CONFIG_SIM_WALLTIME_SIGNAL=y
 CONFIG_START_MONTH=6
 CONFIG_START_YEAR=2008
 CONFIG_SYSTEM_DUMPSTACK=y
 CONFIG_SYSTEM_NSH=y
+CONFIG_TESTING_OSTEST=y