Remove configure tests for assembler CFI support.

Remove configure tests for assembler CFI support.

This patch removes configure tests for assembler CFI support (and
thereby eliminates an architecture-specific case in the main
configure.ac), instead assuming that support is present
unconditionally.

The main test was added in 2003 around the time CFI support was added
to the assembler.  cfi_personality and cfi_lsda support were added to
the assembler in 2006.  cfi_sections support was added in 2009, a few
weeks before binutils 2.20 was released; it's in 2.20, the minimum
supported version, so even that configure test is obsolete.

Tested x86_64 that the installed shared libraries are unchanged by
this patch.

	* configure.ac (libc_cv_asm_cfi_directives): Remove configure
	test.
	* configure: Regenerated.
	* config.h.in (HAVE_ASM_CFI_DIRECTIVES): Remove macro undefine.
	* sysdeps/arm/configure.ac (libc_cv_asm_cfi_directive_sections):
	Remove configure test.
	* sysdeps/arm/configure: Regenerated.
	* sysdeps/nptl/configure.ac: Do not check
	libc_cv_asm_cfi_directives.
	* sysdeps/nptl/configure: Regenerated.
	* sysdeps/x86_64/nptl/configure.ac: Remove file.
	* sysdeps/x86_64/nptl/configure: Remove generated file.
	* b/sysdeps/generic/sysdep.h [HAVE_ASM_CFI_DIRECTIVES]: Make code
	unconditional.
	[!HAVE_ASM_CFI_DIRECTIVES]: Remove conditional code.