Add comment about avoiding VS runtime support to OS::DebugBreak.

R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/23090004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16294 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-win32.cc

@@ -1010,6 +1010,9 @@ void OS::Abort() {
 
 void OS::DebugBreak() {
 #ifdef _MSC_VER
+  // To avoid Visual Studio runtime support the following code can be used
+  // instead
+  // __asm { int 3 }
   __debugbreak();
 #else
   ::DebugBreak();