qmljs: improve suggestion ordering

    change matchStrength sp that a contigous prefix is always preferred

    Task-number: QTCREATORBUG-10638
    Change-Id: I532d93eddae1ad39157ff65e96fc6651200264ab

Change-Id: I1001f5f4b78bac84b8df8ddc4c394c68359f7821
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
qmljs: fix persistent trie tests

Change-Id: I77baa46fd6f01d252fdd7a035d477433659c56dc
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>