BUG: Update ctkDICOMTester to always kill "storescp" process on destr…

…uction

Since the DCMTK executable do not seem to configure a termination handler on
windows (using `SetConsoleCtrlHandler()`) or on Unix (using `sigaction()`),
we speed up testing by simply killing the process.

> On Windows, terminate() posts a WM_CLOSE message to all top-level
> windows of the process and then to the main thread of the process
> itself. On Unix and macOS the SIGTERM signal is sent.
>
> Console applications on Windows that do not run an event loop, or whose
> event loop does not handle the WM_CLOSE message, can only be terminated
> by calling kill().

Source: https://doc.qt.io/qt-5/qprocess.html#terminate

Libs/DICOM/Core/ctkDICOMTester.cpp

@@ -91,8 +91,10 @@ ctkDICOMTesterPrivate::ctkDICOMTesterPrivate(ctkDICOMTester& o): q_ptr(&o)
 //------------------------------------------------------------------------------
 ctkDICOMTesterPrivate::~ctkDICOMTesterPrivate()
 {
-  this->STORESCPProcess->terminate();
-  if (!this->STORESCPProcess->waitForFinished())
+  // Do not wait for the process to finish.
+  // See https://doc.qt.io/qt-5/qprocess.html#terminate
+  // this->STORESCPProcess->terminate();
+  // if (!this->STORESCPProcess->waitForFinished())
     {
     this->STORESCPProcess->kill();
     }