libstdc++: Simplify print_raw function for debug assertions

libstdc++: Simplify print_raw function for debug assertions

Replace two uses of print_raw where it's clearer to just use fprintf
directly. Then the only remaining use of print_raw is as the print_func
argument of pretty_print. When called by pretty_print the count is
either a positive integer or -1, so we can simplify print_raw itself.

Remove the default argument, because it's never used. Remove the check
for nbc == 0, which never happens (but would be harmless if it did).
Replace the conditional expression with a single call to fprintf, using
INT_MAX as the maximum length.

libstdc++-v3/ChangeLog:

	* src/c++11/debug.cc (print_raw): Simplify.
	(print_word): Print indentation by calling fprintf directly.
	(_Error_formatter::_M_error): Print unindented string by calling
	fprintf directly.