I have not been able to reproduce this problem, so adding some extra
debug logs in an attempt to determine what is causing the assertion
failure.
Relates to: #11706
The output from Keyman Core changed in #11172 to emit a
`KM_CORE_IT_INVALIDATE_CONTEXT` action when a frame key is pressed, but
the debugger was not catering for this scenario, causing an assertion
failure.
Fixes: #11486
Fixes: KEYMAN-DEVELOPER-1Y4
Fixes#7649.
emit_keystroke code path in kmx processor was writing directly to the
core queue instead of to the internal kmx processor queue. This caused
it to be out-of-order in the actions sent to the engine/debugger.
Engines didn't really care but it broke the debugger, for example if
only a deadkey was in the buffer and backspace was pressed, Developer
would assert as it would get unexpected context for the deletions.
