Fix Clang-tidy modernize-use-nullptr warnings in some files in source/Target; other minor fixes.

llvm-svn: 261242
diff --git a/lldb/source/Target/Queue.cpp b/lldb/source/Target/Queue.cpp
index 7cfa6fa..9d4032a2 100644
--- a/lldb/source/Target/Queue.cpp
+++ b/lldb/source/Target/Queue.cpp
@@ -7,6 +7,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+// C Includes
+// C++ Includes
+// Other libraries and framework includes
+// Project includes
 #include "lldb/Target/Process.h"
 #include "lldb/Target/Queue.h"
 #include "lldb/Target/QueueList.h"
@@ -32,9 +36,7 @@
     m_process_wp = process_sp;
 }
 
-Queue::~Queue ()
-{
-}
+Queue::~Queue() = default;
 
 queue_id_t
 Queue::GetID ()
@@ -45,10 +47,7 @@
 const char *
 Queue::GetName ()
 {
-    const char *result = NULL;
-    if (m_queue_name.size() > 0)
-        result = m_queue_name.c_str();
-    return result;
+    return (m_queue_name.empty() ? nullptr : m_queue_name.c_str());
 }
 
 uint32_t
@@ -62,7 +61,7 @@
 {
     std::vector<ThreadSP> result;
     ProcessSP process_sp = m_process_wp.lock();
-    if (process_sp.get ())
+    if (process_sp)
     {
         for (ThreadSP thread_sp : process_sp->Threads())
         {
@@ -87,7 +86,6 @@
     return m_running_work_items_count;
 }
 
-
 void
 Queue::SetNumPendingWorkItems (uint32_t count)
 {
@@ -112,11 +110,10 @@
     return m_dispatch_queue_t_addr;
 }
 
-
 const std::vector<lldb::QueueItemSP> &
 Queue::GetPendingItems ()
 {
-    if (m_pending_items.size() == 0)
+    if (m_pending_items.empty())
     {
         ProcessSP process_sp = m_process_wp.lock();
         if (process_sp && process_sp->GetSystemRuntime())