testsuite: tree-ssa: Fix i686/-m32 fails for vector-*.c tests

testsuite: tree-ssa: Fix i686/-m32 fails for vector-*.c tests

FAILs have been reported for several tree-ssa vector-*.c tests
on i686-linux or on x86_64-linux with -m32.
This patch addresses these fails by setting the necessary -msse2 flags.

This patch also streamlines all tests to use dg-options instead
of dg-additional-options.  This is in line with most other tests
in gcc.dg/tree-ssa.

Tested with the following board config in RUNTESTFLAGS:
  --target_board=unix\{-m64,-m32,-m32/-mno-mmx/-mno-sse}

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/satd-hadamard.c: Rename dg-additional-options
	to dg-options.
	* gcc.dg/tree-ssa/vector-10.c: Rename dg-additional-options
	to dg-options and add -msse2 to it.
	* gcc.dg/tree-ssa/vector-11.c: Likewise.
	* gcc.dg/tree-ssa/vector-8.c: Rename dg-additional-options
	to dg-options.
	* gcc.dg/tree-ssa/vector-9.c: Likewise.

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>