Cope with use of the token '>>' inside a template argument list, e.g.,

  vector<vector<double>> Matrix;

In C++98/03, this token always means "right shift". However, if we're in
a context where we know that it can't mean "right shift", provide a
friendly reminder to put a space between the two >'s and then treat it
as two >'s as part of recovery.

In C++0x, this token is always broken into two '>' tokens.

llvm-svn: 65484