AutoTest: Handle conflicting update triggers

If a postponed update should be done for a single parser only and
another full update for all is triggered the latter one would be
ignored which is wrong.
An update for all parsers should always have higher priority and
replace a possible scheduled update for a single parser.

Change-Id: I5e1e446c7dcb9ddbcaed4606ff87a894235b723e
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/autotest/testcodeparser.h

@@ -105,6 +105,7 @@ private:
     QFutureWatcher<TestParseResultPtr> m_futureWatcher;
     QVector<ITestParser *> m_testCodeParsers; // ptrs are still owned by TestFrameworkManager
     QTimer m_reparseTimer;
+    ITestParser *m_updateParser = nullptr;
 };
 
 } // namespace Internal