tests to use new reflect interface. also make tests a real gotest. depends on CL 31107 R=r DELTA=582 (56 added, 194 deleted, 332 changed) OCL=31108 CL=31279
R=r DELTA=32 (0 added, 3 deleted, 29 changed) OCL=30718 CL=30725
tests: all.bash passes, gobuild still works, godoc still works. R=rsc OCL=30096 CL=30102