LLDB: correct event when removing all watchpoints

Previously we incorrectly checked for a "breakpoint changed" event
listener removing all watchpoints (e.g. via
SBTarget::DeleteAllWatchpoints()), although we would emit a "watchpoint
changed" event if there were a listener for 'breakpoint changed'.

This meant that we might not emit a "watchpoint changed" event if there
was a listener for this event.

Correct it to check for the "watchpoint changed" event.

Author: puremourning

lldb/source/Breakpoint/WatchpointList.cpp

@@ -236,7 +236,7 @@ void WatchpointList::RemoveAll(bool notify) {
       wp_collection::iterator pos, end = m_watchpoints.end();
       for (pos = m_watchpoints.begin(); pos != end; ++pos) {
         if ((*pos)->GetTarget().EventTypeHasListeners(
-                Target::eBroadcastBitBreakpointChanged)) {
+                Target::eBroadcastBitWatchpointChanged)) {
           auto data_sp = std::make_shared<Watchpoint::WatchpointEventData>(
               eWatchpointEventTypeRemoved, *pos);
           (*pos)->GetTarget().BroadcastEvent(