Igor Kushnir authored Oct 17, 2020 and Milian Wolff committed Nov 28, 2020

https://commits.kde.org/kdevelop/37ff587ebe2a2c355d71cb583fb5f058c5301ff3
introduced a pure virtual IDebugSession::killDebuggerNow() member
function. DebugSession must override it to become non-abstract and fix
the following compilation error (GCC):
  invalid new-expression of abstract class type ‘Python::DebugSession’

DebugSession::killDebuggerNow() kills the debugger process
unconditionally to mimic the behavior of ~DebugSession().

As far as I can tell, DebugSession::killDebuggerNow() will never be
called, because DebugSession::stopDebugger() switches to EndedState
synchronously and is destroyed before ~DebugController() invokes
&IDebugSession::killDebuggerNow.