ld: Pass $NOPIE_CFLAGS and $NOPIE_LDFLAGS to more ELF visibility tests

ld: Pass $NOPIE_CFLAGS and $NOPIE_LDFLAGS to more ELF visibility 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 the test.  Therefore compile the non-PIC sources with $NOPIE_CFLAGS
and link the test programs with $NOPIE_LDFLAGS.

Commit 922109c71828 ("Pass $NOPIE_CFLAGS to ELF visibility tests") added
$NOPIE_CFLAGS when compiling sh1np.o and sh2np.o.  It missed to add it
to mainnp.o.

ld/testsuite/
	PR ld/21090
	* ld-vsb/vsb.exp (visibility_test): Add support for optional
	ldflags argument and use it when linking the test program.
	(mainnp.o): Compile with $NOPIE_CFLAGS.
	(vnp, vp, vmpnp, vmpp): Link with $NOPIE_LDFLAGS.

Fixes: 922109c71828 ("Pass $NOPIE_CFLAGS to ELF visibility tests")
Bug: https://sourceware.org/PR21090
Signed-off-by: Jens Remus <jremus@linux.ibm.com>