testsuite: fix failing complex add testcases PR103000

testsuite: fix failing complex add testcases PR103000

Some targets have overriden the default unroll factor and so do not have enough
data to succeed for SLP vectorization if loop vect is turned off.

To fix this just always unroll in these testcases.

gcc/testsuite/ChangeLog:

	PR testsuite/103000
	* gcc.dg/vect/complex/fast-math-bb-slp-complex-add-double.c:
	Force unroll.
	* gcc.dg/vect/complex/fast-math-bb-slp-complex-add-float.c: likewise
	* gcc.dg/vect/complex/fast-math-bb-slp-complex-add-pattern-float.c:
	Likewise
	* gcc.dg/vect/complex/fast-math-bb-slp-complex-add-pattern-half-float.c:
	Likewise.