TextEditor: Split the global QuickFixFactory list

It's only ever used in the filtered Cpp/QmlJs variants. Splitting
the class simplifies the code and avoids re-doing filtering over
and over again.

Also inline QuickFixFactory::matchingOperations() into callers

Change-Id: I730756315f2e0321649259ef229631233b12fbdd
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/texteditor/quickfix.cpp

@@ -55,21 +55,3 @@ void QuickFixOperation::setDescription(const QString &description)
 {
     _description = description;
 }
-
-static QList<QuickFixFactory *> g_quickFixFactories;
-
-QuickFixFactory::QuickFixFactory(QObject *parent)
-    : QObject(parent)
-{
-    g_quickFixFactories.append(this);
-}
-
-QuickFixFactory::~QuickFixFactory()
-{
-    g_quickFixFactories.removeOne(this);
-}
-
-const QList<QuickFixFactory *> QuickFixFactory::allQuickFixFactories()
-{
-    return g_quickFixFactories;
-}