QtcProcess: Get rid of setProcessUserEventWhileRunning()

Introduce EventLoopMode enum and pass it to the
QtcProcess::runBlocking() instead. There is no need to
store this setting. By default this value is NoEventLoop.

Change-Id: Icad98b77bec5280b79039b7e5aa4ec408261521c
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

src/plugins/clearcase/clearcaseplugin.cpp

@@ -2354,8 +2354,7 @@ QString ClearCasePluginPrivate::runExtDiff(const FilePath &workingDir, const QSt
     process.setWorkingDirectory(workingDir);
     process.setCodec(outputCodec ? outputCodec : QTextCodec::codecForName("UTF-8"));
     process.setCommand(diff);
-    process.setProcessUserEventWhileRunning();
-    process.runBlocking();
+    process.runBlocking(QtcProcess::WithEventLoop);
     if (process.result() != QtcProcess::FinishedWithSuccess)
         return QString();
     return process.allOutput();