Fix Clang-tidy modernize-use-nullptr warnings; other minor fixes.

llvm-svn: 261179
diff --git a/lldb/source/Target/InstrumentationRuntime.cpp b/lldb/source/Target/InstrumentationRuntime.cpp
index b3b2393..7386c4e 100644
--- a/lldb/source/Target/InstrumentationRuntime.cpp
+++ b/lldb/source/Target/InstrumentationRuntime.cpp
@@ -5,8 +5,12 @@
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
-//===----------------------------------------------------------------------===//
+//===---------------------------------------------------------------------===//
 
+// C Includes
+// C++ Includes
+// Other libraries and framework includes
+// Project includes
 #include "lldb/lldb-private.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Core/PluginManager.h"
@@ -18,12 +22,12 @@
 void
 InstrumentationRuntime::ModulesDidLoad(lldb_private::ModuleList &module_list, lldb_private::Process *process, InstrumentationRuntimeCollection &runtimes)
 {
-    InstrumentationRuntimeCreateInstance create_callback = NULL;
+    InstrumentationRuntimeCreateInstance create_callback = nullptr;
     InstrumentationRuntimeGetType get_type_callback;
     for (uint32_t idx = 0; ; ++idx)
     {
         create_callback = PluginManager::GetInstrumentationRuntimeCreateCallbackAtIndex(idx);
-        if (create_callback == NULL)
+        if (create_callback == nullptr)
             break;
         get_type_callback = PluginManager::GetInstrumentationRuntimeGetTypeCallbackAtIndex(idx);
         InstrumentationRuntimeType type = get_type_callback();