OutputPane: Use setter for priority and fix default visibility

Do not show the buttons of output views with priority < 0 (instead of
only == -1). Reduce the number of buttons that are shown by default to
the essential ones.

Change-Id: I5b44f18537b3033ce9d616f044a8b54b76988783
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/projectexplorer/compileoutputwindow.cpp

@@ -52,6 +52,8 @@ CompileOutputWindow::CompileOutputWindow(QAction *cancelBuildAction) :
 {
     setId("CompileOutput");
     setDisplayName(QCoreApplication::translate("QtC::ProjectExplorer", "Compile Output"));
+    setPriorityInStatusBar(40);
+
     Core::Context context(C_COMPILE_OUTPUT);
     m_outputWindow = new Core::OutputWindow(context, SETTINGS_KEY);
     m_outputWindow->setWindowTitle(displayName());
@@ -178,11 +180,6 @@ void CompileOutputWindow::clearContents()
     m_outputWindow->clear();
 }
 
-int CompileOutputWindow::priorityInStatusBar() const
-{
-    return 50;
-}
-
 bool CompileOutputWindow::canNext() const
 {
     return false;