Fix tst-support_record_failure-2 for run-built-tests = no.

The support/tst-support_record_failure-2.out test attempts to run
built code even if run-built-tests = no, so failing with
build-many-glibcs.py for all architectures whose code cannot be run on
the system running the script.  This patch disables the test in that
case.

Tested for x86_64 (native), and for aarch64 with build-many-glibcs.py.

	* support/Makefile (tests-special): Make definition conditional on
	[$(run-built-tests) = yes].
	($(objpfx)tst-support_record_failure-2.out): Make rule conditional
	on [$(run-built-tests) = yes].