[lldb-dap] Avoid double 'new' events for dyld on Darwin

I got a bug report where a pedantic DAP client complains about getting
two "new" module events for the same UUID. This is caused by the dyld
transition from the on-disk dyld to the shared cache dyld, which share
the same UUID. The transition is not generating an unloaded
event (because we're not really unloading dyld) but we do
get a loaded event (because the load address changed). This PR fixes the
issue by relying on the modules set as the source of truth instead of
relying on the event type.

Author: JDevlieghere

lldb/tools/lldb-dap/DAP.cpp

@@ -1292,22 +1292,17 @@ void DAP::EventThread() {
 
             llvm::StringRef reason;
             bool id_only = false;
-            if (event_mask & lldb::SBTarget::eBroadcastBitModulesLoaded) {
-              modules.insert(module_id);
-              reason = "new";
-            } else {
-              // If this is a module we've never told the client about, don't
-              // send an event.
-              if (!modules.contains(module_id))
-                continue;
-
+            if (modules.contains(module_id)) {
               if (event_mask & lldb::SBTarget::eBroadcastBitModulesUnloaded) {
                 modules.erase(module_id);
                 reason = "removed";
                 id_only = true;
               } else {
                 reason = "changed";
               }
+            } else {
+              modules.insert(module_id);
+              reason = "new";
             }
 
             llvm::json::Object body;