conformtest: Correct time.h XPG3 expectations.

This patch corrects spurious conformtest expectations of getdate and
getdate_err for XPG3.  (This is not based on a full review of the
expectations, so there may be other issues where the header and tests
agree but are both incorrect.)

Tested for x86_64 and x86.

	* conform/data/time.h-data (getdate_err): Do not expect for
	[XPG3].
	(getdate): Likewise.
	* conform/Makefile (test-xfail-XPG3/time.h/conform): Remove
	variable.