[4/n] remove wrapv-*.c special-casing of gcc.dg/vect/ files

The following makes -fwrapv explicit.

	* gcc.dg/vect/vect.exp: Remove special-casing of tests
	named wrapv-*
	* gcc.dg/vect/wrapv-vect-7.c: Add dg-additional-options -fwrapv.
	* gcc.dg/vect/wrapv-vect-reduc-2char.c: Likewise.
	* gcc.dg/vect/wrapv-vect-reduc-2short.c: Likewise.
	* gcc.dg/vect/wrapv-vect-reduc-dot-s8b.c: Likewise.
	* gcc.dg/vect/wrapv-vect-reduc-pattern-2c.c: Likewise.