Revert "Allow tree-ssa.exp to be run by itself" and move some testcases

Revert "Allow tree-ssa.exp to be run by itself" and move some testcases

This reverts commit 9085381f1931cc3667412c8fff91878184835901 as it was
causing default dg-do to be set incorrectly on most targets.
Instead move testcases that are vect related testcase that
use "dg-require-effective-target vect_*" to the vect test area.

ChangeLog:
* gcc.dg/tree-ssa/pr88497-1.c: Move to ...
* gcc.dg/vect/pr88497-1.c: This.
* gcc.dg/tree-ssa/pr88497-2.c: Move to ...
* gcc.dg/vect/pr88497-2.c: This.
* gcc.dg/tree-ssa/pr88497-3.c: Move to ...
* gcc.dg/vect/pr88497-3.c: This.
* gcc.dg/tree-ssa/pr88497-4.c: Move to ...
* gcc.dg/vect/pr88497-4.c: This.
* gcc.dg/tree-ssa/pr88497-5.c: Move to ...
* gcc.dg/vect/pr88497-5.c: This.
* gcc.dg/tree-ssa/pr88497-6.c: Move to ...
* gcc.dg/vect/pr88497-6.c: This.
* gcc.dg/tree-ssa/pr88497-7.c: Move to ...
* gcc.dg/vect/pr88497-7.c: This.

Revert:
* tree-ssa.exp: Set DEFAULT_VECTCFLAGS and DEFAULT_VECTCFLAGS.
Call check_vect_support_and_set_flags also.