get pty by tmux command and close pane when gdb exit

[RoderickChan]

Signed-off-by: roderick [email protected]

Description/Motivation/Screenshots

Sometimes, the old method list(new_ptses - old_ptses)[0] cannot get the right pty while meeting other tmux-pty operations at the same time. And it's better to kill the pane generated by tmux after quitting gdb.

Against which architecture was this tested ?

"Tested" indicates that the PR works and the unit test (i.e. make test) run passes without issue.

• [ ] x86-32
• [x] x86-64
• [ ] ARM
• [ ] AARCH64
• [ ] MIPS
• [ ] POWERPC
• [ ] SPARC
• [ ] RISC-V

Checklist

• [x] My PR was done against the dev branch, not main.
• [x] My code follows the code style of this project.
• [x] My change includes a change to the documentation, if required.
• [x] If my change adds new code, adequate tests have been added.
• [x] I have read and agree to the CONTRIBUTING document.