gfortran: Rely on dg-do-what-default to avoid running pr85853.f90, pr107254.f90 and...

gfortran: Rely on dg-do-what-default to avoid running pr85853.f90, pr107254.f90 and vect-alias-check-1.F90 on non-vector targets

Testcases in gfortran.dg/vect/vect.exp rely on
check_vect_support_and_set_flags to set dg-do-what-default and avoid
running vector tests on non-vector targets. The three testcases in this
patch overwrite the default with dg-do run which causes issues
for non-vector targets.

Removing the dg-do run directive resolves this issue for non-vector
targets (while still running the tests on vector targets).

gcc/testsuite/ChangeLog:

	* gfortran.dg/vect/pr107254.f90: Remove dg-do run directive.
	* gfortran.dg/vect/pr85853.f90: Ditto.
	* gfortran.dg/vect/vect-alias-check-1.F90: Ditto.

Signed-off-by: Patrick O'Neill <patrick@rivosinc.com>