Avoid stray [] in ia64 assembler test.

Avoid stray [] in ia64 assembler test.

Noted in <https://gcc.gnu.org/ml/gcc-patches/2018-11/msg00034.html>.
Fix by adding extra newline in test input is analogous to many such
newlines added in cases where argument to a newly added AC_LANG_SOURCE
had a preprocessor directive on its last line.

	* configure.ac (gcc_cv_as_ia64_ltoffx_ldxmov_relocs): Add newline
	at end of assembler input text.
	* configure: Regenerate.

From-SVN: r265724