c++: parse error with >= in template argument list [PR105436]

c++: parse error with >= in template argument list [PR105436]

This patch fixes an oversight whereby we treated >= as the end of
a template argument.  This causes problems in C++14, because in
cp_parser_template_argument we go different ways for C++14 and C++17:

  /* It must be a non-type argument.  In C++17 any constant-expression is
     allowed.  */
  if (cxx_dialect > cxx14)
    goto general_expr;

so in this testcase in C++14 we get "N" as the template argument but in
C++17 it is the whole "N >= 5" expression.  So in C++14 the remaining
">= 5" triggered the newly-added diagnostic.

	PR c++/105436

gcc/cp/ChangeLog:

	* parser.cc (cp_parser_next_token_ends_template_argument_p): Don't
	return true for CPP_GREATER_EQ.

gcc/testsuite/ChangeLog:

	* g++.dg/parse/template31.C: New test.