[lldb] Use std::make_shared for StopInfoSP (#149612)

Use std::make_shared to create a StopInfoSP, which inherits from
shared_from_this. It's both the most efficient and safest way to create
these objects:

- With make_shared, the object and the control block are allocated
together, which is more efficient.
- With make_shared, the enable_shared_from_this base class is properly
linked to the control block before the constructor finishes, so
shared_from_this() will be safe to use (though still not recommended
during construction).

lldb/source/Target/StopInfo.cpp

@@ -851,8 +851,9 @@ protected:
       // We have to step over the watchpoint before we know what to do:   
       StopInfoWatchpointSP me_as_siwp_sp 
           = std::static_pointer_cast<StopInfoWatchpoint>(shared_from_this());
-      ThreadPlanSP step_over_wp_sp(new ThreadPlanStepOverWatchpoint(
-          *(thread_sp.get()), me_as_siwp_sp, wp_sp));
+      ThreadPlanSP step_over_wp_sp =
+          std::make_shared<ThreadPlanStepOverWatchpoint>(*(thread_sp.get()),
+                                                         me_as_siwp_sp, wp_sp);
       // When this plan is done we want to stop, so set this as a Controlling
       // plan.    
       step_over_wp_sp->SetIsControllingPlan(true);
@@ -1475,13 +1476,13 @@ StopInfoSP StopInfo::CreateStopReasonWithBreakpointSiteID(Thread &thread,
                                                           break_id_t break_id) {
   thread.SetThreadHitBreakpointSite();
 
-  return StopInfoSP(new StopInfoBreakpoint(thread, break_id));
+  return std::make_shared<StopInfoBreakpoint>(thread, break_id);
 }
 
 StopInfoSP StopInfo::CreateStopReasonWithBreakpointSiteID(Thread &thread,
                                                           break_id_t break_id,
                                                           bool should_stop) {
-  return StopInfoSP(new StopInfoBreakpoint(thread, break_id, should_stop));
+  return std::make_shared<StopInfoBreakpoint>(thread, break_id, should_stop);
 }
 
 // LWP_TODO: We'll need a CreateStopReasonWithWatchpointResourceID akin
@@ -1489,67 +1490,67 @@ StopInfoSP StopInfo::CreateStopReasonWithBreakpointSiteID(Thread &thread,
 StopInfoSP StopInfo::CreateStopReasonWithWatchpointID(Thread &thread,
                                                       break_id_t watch_id,
                                                       bool silently_continue) {
-  return StopInfoSP(
-      new StopInfoWatchpoint(thread, watch_id, silently_continue));
+  return std::make_shared<StopInfoWatchpoint>(thread, watch_id,
+                                              silently_continue);
 }
 
 StopInfoSP StopInfo::CreateStopReasonWithSignal(Thread &thread, int signo,
                                                 const char *description,
                                                 std::optional<int> code) {
   thread.GetProcess()->GetUnixSignals()->IncrementSignalHitCount(signo);
-  return StopInfoSP(new StopInfoUnixSignal(thread, signo, description, code));
+  return std::make_shared<StopInfoUnixSignal>(thread, signo, description, code);
 }
 
 StopInfoSP StopInfo::CreateStopReasonWithInterrupt(Thread &thread, int signo,
                                                    const char *description) {
-  return StopInfoSP(new StopInfoInterrupt(thread, signo, description));
+  return std::make_shared<StopInfoInterrupt>(thread, signo, description);
 }
 
 StopInfoSP StopInfo::CreateStopReasonToTrace(Thread &thread) {
-  return StopInfoSP(new StopInfoTrace(thread));
+  return std::make_shared<StopInfoTrace>(thread);
 }
 
 StopInfoSP StopInfo::CreateStopReasonWithPlan(
     ThreadPlanSP &plan_sp, ValueObjectSP return_valobj_sp,
     ExpressionVariableSP expression_variable_sp) {
-  return StopInfoSP(new StopInfoThreadPlan(plan_sp, return_valobj_sp,
-                                           expression_variable_sp));
+  return std::make_shared<StopInfoThreadPlan>(plan_sp, return_valobj_sp,
+                                              expression_variable_sp);
 }
 
 StopInfoSP StopInfo::CreateStopReasonWithException(Thread &thread,
                                                    const char *description) {
-  return StopInfoSP(new StopInfoException(thread, description));
+  return std::make_shared<StopInfoException>(thread, description);
 }
 
 StopInfoSP StopInfo::CreateStopReasonProcessorTrace(Thread &thread,
                                                     const char *description) {
-  return StopInfoSP(new StopInfoProcessorTrace(thread, description));
+  return std::make_shared<StopInfoProcessorTrace>(thread, description);
 }
 
 StopInfoSP StopInfo::CreateStopReasonHistoryBoundary(Thread &thread,
                                                      const char *description) {
-  return StopInfoSP(new StopInfoHistoryBoundary(thread, description));
+  return std::make_shared<StopInfoHistoryBoundary>(thread, description);
 }
 
 StopInfoSP StopInfo::CreateStopReasonWithExec(Thread &thread) {
-  return StopInfoSP(new StopInfoExec(thread));
+  return std::make_shared<StopInfoExec>(thread);
 }
 
 StopInfoSP StopInfo::CreateStopReasonFork(Thread &thread,
                                           lldb::pid_t child_pid,
                                           lldb::tid_t child_tid) {
-  return StopInfoSP(new StopInfoFork(thread, child_pid, child_tid));
+  return std::make_shared<StopInfoFork>(thread, child_pid, child_tid);
 }
 
 
 StopInfoSP StopInfo::CreateStopReasonVFork(Thread &thread,
                                            lldb::pid_t child_pid,
                                            lldb::tid_t child_tid) {
-  return StopInfoSP(new StopInfoVFork(thread, child_pid, child_tid));
+  return std::make_shared<StopInfoVFork>(thread, child_pid, child_tid);
 }
 
 StopInfoSP StopInfo::CreateStopReasonVForkDone(Thread &thread) {
-  return StopInfoSP(new StopInfoVForkDone(thread));
+  return std::make_shared<StopInfoVForkDone>(thread);
 }
 
 ValueObjectSP StopInfo::GetReturnValueObject(StopInfoSP &stop_info_sp) {