c++: remove '_sfinae' suffix from functions

The functions

  abstract_virtuals_error
  cxx_constant_value
  get_target_expr
  instantiate_non_dependent_expr
  require_complete_type

are each just a non-SFINAE-enabled wrapper for the corresponding
SFINAE-enabled version that's suffixed by '_sfinae'.  But this suffix is
at best redundant since a 'complain' parameter already broadly conveys
that a function is SFINAE-enabled, and having two such versions of a
function is less concise than just using a default argument for 'complain'
(and arguably no less mistake prone).

So this patch squashes the two versions of each of the above functions
by adding a default 'complain' argument to the SFINAE-enabled version
whose '_sfinae' suffix we then remove.

gcc/cp/ChangeLog:

	* call.cc (build_conditional_expr): Adjust calls to
	'_sfinae'-suffixed functions.
	(build_temp): Likewise.
	(convert_like_internal): Likewise.
	(convert_arg_to_ellipsis): Likewise.
	(build_over_call): Likewise.
	(build_cxx_call): Likewise.
	(build_new_method_call): Likewise.
	* constexpr.cc (cxx_eval_outermost_constant_expr): Likewise.
	(cxx_constant_value_sfinae): Rename to ...
	(cxx_constant_value): ... this.  Document its default arguments.
	(fold_non_dependent_expr): Adjust function comment.
	* cp-tree.h (instantiate_non_dependent_expr_sfinae): Rename to ...
	(instantiate_non_dependent_expr): ... this.  Give its 'complain'
	parameter a default argument.
	(get_target_expr_sfinae, get_target_expr): Likewise.
	(require_complete_type_sfinae, require_complete_type): Likewise.
	(abstract_virtuals_error_sfinae, abstract_virtuals_error):
	Likewise.
	(cxx_constant_value_sfinae, cxx_constant_value): Likewise.
	* cvt.cc (build_up_reference): Adjust calls to '_sfinae'-suffixed
	functions.
	(ocp_convert): Likewise.
	* decl.cc (build_explicit_specifier): Likewise.
	* except.cc (build_noexcept_spec): Likewise.
	* init.cc (build_new_1): Likewise.
	* pt.cc (expand_integer_pack): Likewise.
	(instantiate_non_dependent_expr_internal): Adjust function
	comment.
	(instantiate_non_dependent_expr): Rename to ...
	(instantiate_non_dependent_expr_sfinae): ... this.  Document its
	default argument.
	(tsubst_init): Adjust calls to '_sfinae'-suffixed functions.
	(fold_targs_r): Likewise.
	* semantics.cc (finish_compound_literal): Likewise.
	(finish_decltype_type): Likewise.
	(cp_build_bit_cast): Likewise.
	* tree.cc (build_cplus_new): Likewise.
	(get_target_expr): Rename to ...
	(get_target_expr_sfinae): ... this.  Document its default
	argument.
	* typeck.cc (require_complete_type): Rename to ...
	(require_complete_type_sfinae): ... this.  Document its default
	argument.
	(cp_build_array_ref): Adjust calls to '_sfinae'-suffixed
	functions.
	(convert_arguments): Likewise.
	(cp_build_binary_op): Likewise.
	(build_static_cast_1): Likewise.
	(cp_build_modify_expr): Likewise.
	(convert_for_initialization): Likewise.
	* typeck2.cc (abstract_virtuals_error): Rename to ...
	(abstract_virtuals_error_sfinae): ... this. Document its default
	argument.
	(build_functional_cast_1): Adjust calls to '_sfinae'-suffixed
	functions.