use thread-local variable in scripts/function_time.kp

use per-cpu variable to account function durtion is
problematic, turn to use thread-local variable, in ktap,
we use associative array to be thread-local variable.

In future, we need to find another efficent thread-local
variable handling.

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@gmail.com>
some tiny update on scripts/*.kp

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@gmail.com>