[Demangle PATCH] Some pre-fix cleanups

[Demangle PATCH] Some pre-fix cleanups

https://gcc.gnu.org/ml/gcc-patches/2017-09/msg00983.html

	* cp-demangle.c (is_fnqual_component_type): Reimplement using
	FNQUAL_COMPONENT_CASE.
	(d_encoding): Hold bare_function_type in local var.
	(d_local_name): Build name in both cases and build result once.
	Collapse switch-if to single conditional.
	* testsuite/demangle-expected: Realign blank lines with tests.

From-SVN: r252802