I create a new option "-tT" for gcore, so that it could display bt for user space

directly inside crash itself, without needing to dump a separated core file image,

and analyze it in a different gdb env.

The attached patch is directly based on below patch, and verify over ARM platform.

Before use the corresponding gcore command, we need set env in crash by:

crash>> gdb set solib-search-path [system lib path]

crash>> gdb file [user space program symbol file]

crash>> gcore -t [user space thread id]

Thanks,

Lei