Another attempt to fix Win build.

Review URL: http://codereview.chromium.org/6825061

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7577 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/platform-win32.cc

@@ -1534,7 +1534,6 @@ void Thread::Start() {
                      this,
                      0,
                      NULL));
-  ASSERT(IsValid());
 }