tst-ld-sse-use.sh is a bash script, not a POSIX shell script, and so
needs to be run with $(BASH) not $(SHELL) to avoid errors of the form:
../sysdeps/x86/tst-ld-sse-use.sh: 41: ../sysdeps/x86/tst-ld-sse-use.sh: declare: not found
(when /bin/sh is dash). This patch makes that change.
Tested for x86_64.
* sysdeps/x86/Makefile ($(objpfx)tst-ld-sse-use.out): Run script
with $(BASH) not $(SHELL).