make table to be pre-allocated and disallow table resize

New function for pre-allocate table entries:
	 table.new(narr, nrec)

For ptable, use:
	ptable(narr, nrec)

If no parameter given, then ktapvm pre-allocate default size:
	default narr: 128
	default nrec: 2048

if table entries exceed the default number, ktapvm will exit
with overflow error.

If default value is not enough for script, user must to enlarge
the vaule by above two functions.

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