Refactoring event click-drag detection broke click detection for
simulated events. Resolve this by sharing logic for update previous
values in `wmWindow.eventstate` for regular event handling
(no functional changes for non-simulated events). Failure to detect
clicks for simulated events broke the undo test
`test_undo.view3d_multi_mode_select` in `../lib/tests/ui_simulate/run.py`.
All undo tests now pass.
a4ed0f51c1