x86: Pass $NOPIE_LDFLAGS to undefined weak tests

x86: Pass $NOPIE_LDFLAGS to undefined weak tests

Some distributions configure GCC with --enable-default-pie, so that it
defaults to compile with -fPIE and link with -pie, which is unexpected
by some of the tests.  Therefore link the PDE test programs with
$NOPIE_LDFLAGS to disable PIE.

This complements commit a7eaf017f959 ("Use NOPIE_CFLAGS and
NOPIE_LDFLAGS to disable PIE").

ld/testsuite/
	PR ld/21090
	* ld-x86-64/x86-64.exp (undefined_weak): Use NOPIE_LDFLAGS to
	disable PIE for the non-PIE versions of the test.

Bug: https://sourceware.org/PR21090
Signed-off-by: Jens Remus <jremus@linux.ibm.com>