Require binutils 2.25 or later to build glibc.

This patch implements a requirement of binutils >= 2.25 (up from 2.22)
to build glibc.  Tests for 2.24 or later on x86_64 and s390 are
removed.  It was already the case, as indicated by buildbot results,
that 2.24 was too old for building tests for 32-bit x86 (produced
internal linker errors linking elf/tst-gnu2-tls1mod.so).  I don't know
if any configure tests for binutils features are obsolete given the
increased version requirement.

Tested for x86_64.

	* configure.ac (AS): Require binutils 2.25 or later.
	(LD): Likewise.
	* configure: Regenerated.
	* sysdeps/s390/configure.ac (AS): Remove version check.
	* sysdeps/s390/configure: Regenerated.
	* sysdeps/x86_64/configure.ac (AS): Remove version check.
	* sysdeps/x86_64/configure: Regenerated.
	* manual/install.texi (Tools for Compilation): Document
	requirement for binutils 2.25 or later.
	* INSTALL: Regenerated.