Some actions stay in redo stack but cannot be redone

[GerdP]

From ticket:16875#comment:7

There is still something wrong here. Try this:
1) Open sample file raw-attachment/ticket/16875/dupway.osm + run validator
2) Select Building duplicated nodes (4) and click "Fix"
3) Press Ctrl+Z two times
4) Add a new node somewhere else
The new action from 4) is added to the command stack, but the previously "undoned" actions are not removed.
This seems not to depend on the fix action, it also happens during normal edits.

With r13722 I don't see this behaviour.

[GerdP]

The attached patch seems to solve the problem but if I got that right ensureTreesConsistency() should do that already, so I'll dig into this again.

[GerdP]

In 14562/josm:

fix #16911 regression from r13729 : make sure that redo tree is cleared when a command is added after one or more undos