tabs are closable if non-terminated jobs are stopped

[Karl-Philipp Richter]

Just like `gnome-terminal` refuses to close a tab or the window if a process is running in the foreground, it should refuse to close if a started job has been interrupted using Ctrl+Z.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: gnome-terminal 3.24.2-0ubuntu4
Uname: Linux 4.15.0-041500-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.7-0ubuntu3.7
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Feb 12 01:07:35 2018
JournalErrors:
 Error: command ['journalctl', '-b', '--priority=warning', '--lines=1000'] failed with exit code 1: Hint: You are currently not seeing messages from other users and the system.
       Users in the 'systemd-journal' group can see all messages. Pass -q to
       turn off this notice.
 No journal files were opened due to insufficient permissions.
SourcePackage: gnome-terminal
UpgradeStatus: No upgrade log present (probably fresh install)

[Egmont Koblinger (egmont-gmail)]

Good idea, thanks! I've opened an upstream gnome-terminal bugreport about it:
https://bugzilla.gnome.org/show_bug.cgi?id=793521