Reduce iteration counts for gcc.dg/vect/tsvc tests.

testsuite/
	* gcc.dg/vect/tsvc/tsvc.h (iterations): Allow to override,
	default to 10.
	(get_expected_result): Add values for iterations counts
	10, 256 and 3200.
	(run): Add code to output values for new iterations counts.
	* gcc.dg/vect/tsvc/vect-tsvc-s1119.c (dg-additional-options):
	Add -Diterations=LEN_2D .
	* gcc.dg/vect/tsvc/vect-tsvc-s115.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s119.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s125.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s2102.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s2233.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s2275.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s231.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s235.c: Likewise.
	* gcc.dg/vect/tsvc/vect-tsvc-s176.c: (dg-additional-options):
	Add -Diterations=3200 .
	[!run_expensive_tests]: dg-additional-options "-DTRUNCATE_TEST" .
	[TRUNCATE_TEST]: Set m to 32.