Adjust goyacc.go to produce code that is gofmt-compliant whenever it is easy to do so. Also changed two lines in cpyact that appeared to be bugs.

Also updated units.y to remove a few other errors.

After this change, units.go has only two style errors: an extra newline at the top of the file, and yys misaligned in yySymType.

R=rsc
CC=golang-dev
https://golang.org/cl/5265047