testsuite: enable fast-math-complex-* testcases.

testsuite: enable fast-math-complex-* testcases.

As pointed out in PR105095 these tests weren't running, mainly because the .exp
file contains a filter on the first character so it can distinguish between
fast-math-bb-slp-* and fast-math-*, my test started with `c` and so didn't get
found.

This patch adds `c` to the list of filters and also updates the output and
required guards for the testcases now that they run.

gcc/testsuite/ChangeLog:

	PR testsuite/105095
	* gcc.dg/vect/complex/fast-math-complex-add-double.c: Update for codegen.
	* gcc.dg/vect/complex/fast-math-complex-add-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-add-half-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-add-pattern-double.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-add-pattern-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-add-pattern-half-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mla-half-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mls-double.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mls-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mls-half-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mul-double.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mul-float.c: Likewise.
	* gcc.dg/vect/complex/fast-math-complex-mul-half-float.c: Likewise.
	* gcc.dg/vect/vect.exp: Add extra letter to filter.