When a user exits KDevelop while debugging a program, a queued call to
MIDebugger::readyReadStandardOutput() may be invoked during or after
~CorePrivate(). If this happens after ~DebugController() (which is the
parent of BreakpointModel), a crash is likely, because
readyReadStandardOutput() indirectly calls
MIBreakpointController::updateFromDebugger(), which assumes that
BreakpointModel is not null (as do all other MIBreakpointController's
member functions).

Note that MIDebugger::readyReadStandardOutput() after ~DebugController()
can be invoked both from inside ~MIDebugger() (more precisely, from
inside the QProcess::waitForFinished() call) and before the destructor.

There is no need to process a debugger's standard output and risk a
crash when KDevelop has almost finished shutting down.

BUG: 425993
FIXED-IN: 5.6.1