[lldb-vscode] attempt to fix flakiness

There are many tests failing intermittently for lldb-vscode after
https://reviews.llvm.org/rGaa4685c0fb3aab5acb90be5fd3eb5ba8bf1e3211. I'm
unsure if this actually the culprit, so I'm softly removing that feature
to see if that fixes the issue.

lldb/tools/lldb-vscode/lldb-vscode.cpp

@@ -1411,7 +1411,8 @@ void request_modules(const llvm::json::Object &request) {
 // }
 void request_initialize(const llvm::json::Object &request) {
   g_vsc.debugger = lldb::SBDebugger::Create(true /*source_init_files*/);
-  g_vsc.progress_event_thread = std::thread(ProgressEventThreadFunction);
+  // TODO: reenable once confirmed that this doesn't make the buildbots flaky
+  // g_vsc.progress_event_thread = std::thread(ProgressEventThreadFunction);
 
   // Create an empty target right away since we might get breakpoint requests
   // before we are given an executable to launch in a "launch" request, or a