testsuite: more (mostly cosmetic) dg- whitespace fixes

testsuite: more (mostly cosmetic) dg- whitespace fixes

Some of these are harmless but still inconsistent (and asking for trouble
given it may give people the wrong idea about similar "style").

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/gen-attrs-6.C: Surround 'target' by whitespace.
	* gcc.target/aarch64/atomic-inst-ldlogic.c: Fix 'dg-final' whitespace.
	* gcc.target/arm/short-vfp-1.c: Ditto.
	* gcc.target/bfin/l2.c: Fix 'dg-bfin-processors' whitespace.
	* gcc.target/i386/avx512fp16-vmovw-1b.c: Surround 'target' by whitespace.
	* gcc.target/i386/sse2-float16-5.c: Ditto.
	* gcc.target/powerpc/fold-vec-perm-longlong.c: Ditto.